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HomeMy WebLinkAboutSW8991202_HISTORICAL FILE_20000329STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW8 C' o l wz DOC TYPE ❑ CURRENT PERMIT ❑ APPROVED PLANS HISTORICAL FILE ❑ COMPLIANCE EVALUATION INSPECTION DOC DATE 2000 0 3 2 q YYYYMMDD State of North Carolina Department of Environment and Natural Resources Wilmington Regional Office James B. Hunt, Jr., Governor Bill Holman, Secretary Division of Water Quality Mr. David A. Horton, Owner 128 Little Nine Dr. Morehead City, NC 28557 Dear Mr. Horton: as N C D E N NcR CAROUNA DEPARTMENT OF ENVIRONMENT MO NA URAL RESOURCES March 29, 2000 Subject: Permit No. SW8991202 David A. Horton High Density Subdivision Stormwater Project Carteret County The Wilmington Regional Office received a complete Stormwater Management Permit Application for David A. Horton on March 24, 2000. Staff review of the plans and specifications has determined that the project, as proposed, will comply with the Stormwater Regulations set forth in Title 15A NCAC 2H.1000. We are forwarding Permit No. SW8 991202, dated March 29, 2000, for the construction of the project, David A. Horton. This permit shall be effective from the date of issuance until March 29, 2010, and shall be subject to the conditions and limitations as specified therein. Please pay special attention to the Operation and Maintenance requirements in this permit. Failure to establish an adequate system for operation and maintenance of the stormwater management system will result in future compliance problems. If any parts, requirements, or limitations contained in this permit are unacceptable, you have the right to request an adjudicatory hearing upon written request within thirty (30) days following receipt of this permit. This request must be in the form of a written petition, conforming to Chapter 150B of the North Carolina General Statutes, and filed with the Office of Administrative Hearings, P.O. Drawer 27447, Raleigh, NC 27611-7447. Unless such demands are made this permit shall be final and binding. If you have any questions, or need additional information concerning this matter, please contact Scott Vinson, or me at (910)395-3900. Sincerely, Rick Shiver Water Quality Regional Supervisor RSS/:sav S:\WQS\STORMWAT\PERMIT\991202.MAR cc: C.T. Clayton Katrina Marshall, Carteret County Inspections Scott Vinson Wilmington Regional Office Central Fdes 127 Cardinal Dr. Est., Wilmington, North Carolina 28405 Telephone 910-395-3900 FAX 910-350-2004 An Equal Opportunity Affirmative Action Employer 50% recycled/10% post -consumer paper State Stormwater Management Systcros Permit No. SW8 991202 STATE OF NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES DIVISION OF WATER QUALITY STATE STORMWATER MANAGEMENT PERMIT HIGH DENSITY DEVELOPMENT In accordance with the provisions of Article 21 of Chapter 143, General Statutes of North Carolina as amended, and other applicable Laws, Rules, and Regulations PERMISSION IS HEREBY GRANTED TO David A. Horton, Owner Carteret County FOR THE construction, operation and maintenance of a wet detention pond and a sand filter in compliance with the provisions of 15A NCAC 2H .1000 (hereafter referred to as the "stormwater rules') and the approved stormwater management plans and specifications and other supporting data as attached and on file with and approved by the Division of Water Quality and considered a part of this permit. This permit shall be effective from the date of issuance until March 29, 2010 and shall be subject to the following specified conditions and limitations: I. DESIGN STANDARDS 1. This permit is effective only with respect to the nature and volume of stormwater described in the application and other supporting data. 2. This stormwater system has been approved for the management of stormwater runoff as described on page 3 of this permit, the Project Data Sheet. The subdivision is permitted for 15 lots, each allowed 80% of built -upon area, see Attachment A for square footage of built -upon area per lot. 3. Approved plans and specifications for this project are incorporated by reference and are enforceable parts of the permit. 4. This pond must be operated with a 30' vegetated filter. 2 _ .. State Stormwater Management Systems Permit No. SW8 991202 DIVISION OF WATER QUALITY PROJECT DATA SHEET Project Name: David A. Horton Permit Number: SW8 991202 Location: Carteret County Applicant: Mr. David A. Horton, Owner Mailing Address: David A. Horton 128 Little Nine Dr. Morehead City, NC 28557 Application Date: March 24, 2000 Name of Receiving Stream / Index #: Newport River / WOK03 21-(1) Classification of Water Body: "C" If Class SA, chloride sampling results: n/a Design Storm: F, Pond Depth, feet: 6.00 Permanent Pool Elevation, FMSL: 22.00 Total Impervious Surfaces, ftz: 284,353 15 lots at 80%, ftz: 243,843 Roads/Parking, ftz 40,510 Other, ftz n/a Offsite Area entering Pond, ftz: none, per Engineer Required Surface Area, ftz:. 11,803 Provided Surface Area, ftz: 12,550 Required Storage Volume, ft3: 23,114 Provided Storage Volume, ft3: 25,527 Temporary Storage Elevation, FMSL: 23.85 Controlling Orifice: 2.00" � pipe I State Stormwater Management Systems Permit No. SW8 991202 DIVISION OF WATER QUALITY PROJECT DATA SHEET Project Name: David A. Horton Permit Number: SW8 991202 Location: Carteret County Applicant: Mr. David A. Horton, Owner Mailing Address: David A. Horton 128 Little Nine Dr. Morehead City, NC 28557 Application Date: March 24, 2000 Name of Receiving Stream / Index #: Newport River / WOK03 21-(1) Classification of Water Body: "C" If Class SA, chloride sampling results: n/a Design Storm: V Sand Filter Depth, inches: 22.00 Sand Filter Top Elevation, FMSL: 24.50 Total Impervious Surfaces, ft': 3,700 15 lots at 80%, ft': n/a Roads/Parking, ft' 3,700 Other, ft' n/a Offsite Area entering Sand Filter, ft': Required Surface Area, ft': Provided Surface Area, ft2: Required Storage Volume, ft': Provided Storage Volume, ft': Controlling Orifice: none, per Engineer Sediment Chamber Sand Filter Chamber 30.75 30.75 31.00 31.00 46.12 46.12 46.50 46.50 4.00" � pipe 11 State Stormwater Management Systems Permit No. SW8 991202 II. SCHEDULE OF COMPLLANCE No homeowner/lot owner/developer shall fill in, alter, or pipe any drainage feature (such as swales) shown on the approved plans as part of the stormwater management system without submitting a revision to the permit and receiving approval from the Division. 2. The permittee is responsible for verifying that the proposed built -upon area does not exceed the allowable built -upon area. Once the lot transfer is complete, the built -upon area may not be revised without approval from the Division of Water Quality, and responsibility for meeting the built -upon area limit is transferred to the individual property owner. The following items will require a modification to the permit: a. Any revision to the approved plans, regardless of size. b. Project name change. C. Transfer of ownership. d. Redesign or addition to the approved amount of built -upon area. e. Further subdivision of the project area. f. Filling in, altering, or piping of any vegetative conveyance shown on the approved plan. 4. The Director may determine that other revisions to the project should require a modification to the permit. The Director may notify the permittee when the permitted site does not meet one or more of the minimum requirements of the permit. Within the time frame specified in the notice, the permittee shall submit a written time schedule to the Director for modifying the site to meet minimum requirements. The permittee shall provide copies of revised plans and certification in writing to the Director that the changes have been made. 6. The stormwater management system shall be constructed in it's entirety, vegetated and operational for its intended use prior to the construction of any built -upon surface except roads. During construction, erosion shall be kept to a minimum and any eroded areas of the system will be repaired immediately..,,, The permittee grants permission to DENR Staff to enter the property for the purposes of inspecting the project for compliance with the conditions of this permit. Upon completion of construction, prior to issuance of a Certificate of Occupancy, and prior to operation of this permitted facility, a certification must be received from an appropriate designer for the system installed certifying that the permitted facility has been installed in accordance with this permit, the approved plans and specifications, and other supporting documentation. Any deviations from the approved plans and specifications must be noted on the Certification. 10. Decorative spray fountains will not be allowed in the stormwater treatment system. 11. If the stormwater system was used as an Erosion Control device, it must be restored to design condition prior to operation as a stormwater treatment device, and prior to occupancy of the facility. 12. Prior to transfer of ownership, the pond must be inspected by DWQ personnel, and determined to be in compliance with all permit conditions. Records of maintenance activities will be required. State Stormwater Management Systems Permit No. SW8 991202 13. The permittee shall at all times provide the operation and maintenance necessary to assure the permitted stormwater system functions at optimum efficiency. The approved Operation and Maintenance Plan must be followed in its entirety and maintenance must occur at the scheduled intervals including, but not limited to: a. Semiannual scheduled inspections (every 6 months). b. Sediment removal. C. Mowing and revegetation of side slopes. d. Immediate repair of eroded areas. e. Maintenance of side slopes in accordance with approved plans and specifications. f. Debris removal and unclogging of outlet structure, orifice device and catch basins and piping. g. Access to the outlet structure must be available at all times. h. The vegetated filter shall be kept free of erosion. The spreader mechanism shall be kept free of sediment and trash, and shall evenly distribute the runoff across the width of the filter. 14. Records of maintenance activities must be kept and made available upon request to authorized personnel of DWQ. The records will indicate the date, activity, name of person performing the work and what actions were taken. 15. Prior to the sale of any lot, deed restrictions must be recorded which limit the built -upon area per lot to the amount as shown on the Project Data Sheet, per Section I, Part 2. The recorded statements must follow the form: a. "The maximum built -upon area per lot is 80% of each lot, see Attachment A for the square footage of built -upon area per lot. This allotted amount includes any built -upon area constructed within the lot property boundaries, and that portion of the right-of-way between the front lot line and the edge of the pavement. Built upon area includes, but is not limited to, structures, asphalt, concrete, gravel, brick, stone, slate, and coquina, but does not include raised, open wood decking, or the water surface of swimming pools." b. "The covenants pertaining to stormwater regulations may not be changed or deleted without concurrence of the State." C. "Alteration of the drainage as shown on the approved plan may not take place without the concurrence of the State." d. "Lots within CAMA's Area of Environmental Concern may be subject to a reduction in their allowable built -upon area due to CAMA regulations." e. "All runoff on the lot must drain into the permitted system. This may be accomplished through providing roof drain gutters which drain to the street, grading the lot to drain toward the street, or grading perimeter swales and directing them into the pond or street. Lots that naturally drain into the system are not required to provide these measures." 16. A copy of the recorded deed restrictions must be submitted to the Division within 30 days of the date of recording the plat, and prior to selling lots. The recorded copy must bear the signature of the Permittee, the deed book number and page, and stamp/signature of the Register of Deeds. 0 State Stormwater Management Systems Permit No. SW8 991202 17. This permit shall become voidable unless the facilities are constructed in accordance with the conditions of this permit, the approved plans and specifications, and other supporting data. 18. A copy of the approved plans and specifications shall be maintained on file by the Permittee for a minimum of ten years from the date of the completion of construction. III. GENERAL CONDITIONS This permit is not transferable. In the event there is a desire for the facilities to change ownership, or there is a name change of the Permittee, a "Name/Ownership Change Form" must be submitted to the Division of Water Quality accompanied by appropriate documentation from the parties involved, such as a copy of the deed of trust. Other supporting materials, such as a signed Operation and Maintenance plan in the case of engineered systems, will also be required. The project must be in good standing with DWQ. The approval of this request will be considered on its merits and may or may not be approved. Failure to abide by the conditions and limitations contained in this permit may subject the Permittee to enforcement action by the Division of Water Quality, in accordance with North Carolina General Statute 143-215.6A to 143-215.6C. 3. The issuance of this permit does not preclude the Permittee from complying with any and all statutes, rules, regulations, or ordinances which may be imposed by other government agencies (local, state, and federal) which have jurisdiction. In the event that the facilities fail to perform satisfactorily, including the creation of nuisance conditions, the Permittee shall take immediate corrective action, including those as may be required by this Division, such as the construction of additional or replacement stormwater management systems. 5. The permit may be modified, revoked and reissued or terminated for cause. The filing of a request for a permit modification, revocation and reissuance or termination does not stay any permit condition. 6. Permittee grants perm4sion to staff of the DWQ to access the property for the purposes of inspecting the stormwater facilities during normal business hours. 7. The permittee shall notify the Division of any mailing address changes within 30 days. Permit issued this the 29th day of March, 2000. NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION l� = Kerr T. Stevens, Director Division of Water Quality By Authority of the Environmental Management Commission Permit Number SW8 991202 State Stormwater Management Systems Permit No. SW8 991202 David A. Horton Stormwater Permit No. SW8 991202 Carteret County Page 1 of 2 Designer's Certification 1, as a duly registered in the State of North Carolina, having been authorized to observe (periodically/weekly/full time) the construction of the project, for (Project Owner) hereby state that, to the best of my abilities, due care and diligence was used in the observation of the project construction such that the construction was observed to be built within substantial compliance and intent of the approved plans and specifications. The checklist of items on page 2 of this form are a part of this Certification. Noted deviations from approved plans and specifications: SEAL Signature Registration Number Date State Stormwater Management Systems Permit No. SW8 991202 Certification Requirements: Page 2 of 2 1. The drainage area to the system contains approximately the permitted acreage. 2. The drainage area to the system contains no more than the permitted amount of built -upon area. 3. All the built -upon area associated with the project is graded such that the runoff drains to the system. 4. The outlet/bypass structure elevations are per the approved plan. 5. The outlet structure is located per the approved plans. 6. Trash rack is provided on the outlet/bypass structure. All slopes are grassed with permanent vegetation. 8. Vegetated slopes are no steeper than 3:1. 9. The inlets are located per the approved plans and do not cause short-circuiting of the system. 10. The permitted amounts of surface area and/or volume have been provided. _11. Required drawdown devices are correctly sized per the approved plans. 12. All required design depths are provided. _13. All required parts of the system are provided, such as a vegetated shelf, a forebay, and the vegetated filter. 14. The overall dimensions of the system, as shown on the approved plans, are provided. cc: NCDENR-DWQ Regional Office Katrina Marshall, Carteret County Building Inspector H?r&-&k4If#Mt Al Stormwater Management Built -upon Areas ' Each Lot LOT 5Q.FT. 80% 1 18,790 15,032 2 18,148 14,518 3 18,931 15,145 4 17,590 14,072 5 17,488 13,990 6 17,385 13,908 7 21,894 17,515 8 17,368 13,894 10 19,344 15,475 11 20,988 16,790 12 24,219 19,375 13 23,770 19,016 14 27,957 22,366 15 22,699 18,159 16 18,233 14,586 243,843 Average lot impervious 16,256.21 Q URMWATER E C E I V ED IUnlil DEC,O 1 t999 PROJ d Dw�� David A. Horton 01126/2000 s.2;.?,i?.rz�rri:OF?F,ICEi USE '"ON LY,� T rrz�«,�.n.��';'`�;`;��'�v.. Date Received Fee Paid Permit Number a State of North Carolina Department of Environment and Natural Resources Division of Water Quality STORMWATER MANAGEMENT PERMIT APPLICATION FORM This form may be photocopied for use as an original I. GENERAL INFORMATION 1. Applicants name (specify the name of the corporation, individual, etc. who owns the project): David A. Horton 2. Print Owner/Signing Official's name and title (person legally responsible for facility and compliance): David A. Horton 3. Mailing Address for person listed in item 2 above: 128 Little.'Nine,Dr', City: Telephone Number: 252 1 444-13 State: NC Zip: 28557 4. Project Name (subdivision, facility, or establishment none - should be consistent with project name on plans, specifications, letters, operation and maintenance agreements, etc.): David A. Horton 5. Location of Project (street address): Little Nine Dr. City: Morehead City County: Carteret 6. Directions to project (from nearest major intersection): At intersection of U.S. Hwy 70 & NC Hwy 24, head west toward Newport. Little Nine Drive will be on the left. 7. Latitude: 3 4 ° 4 4 ' 21 " Longitude: 7 6 ° 4 8 ' 3 6 " of project 8. Contact person who, can answer questions about the project: Name: David A. Horton Telephone Number: ( 252 1 444-1355 it. PERMIT INFORMATION: 1. Specify whether project is (check one): X New Renewal Modification Form SWU-101 Version 3.99 Page 1 of 4 2. If this application is being submitted as the result of a renewal or modification to an existing permit, list the.' existing permit number and its issue date (if known) 3. Specify the type of project (check one): _Low Density X High Density _Redevelop _General Permit _Other 4. Additional Project Requirements (check applicable blanks): CAMAMajor XSedmentation/Erosion Control _404/401Permit Nl'DESStormwater Information on require, state permits can be obtained by contacting the Customer Service Center at 1-877-623-6748. III. PROJECT INFORMATION 1. In the space provided below, summarize how stormwater will be treated. Also attach a detailed narrative (one to two pages) describing stormwater management for the project. Stormwater from site shall go through drainage: -structures. Then into a forebay of a stormwater pond. It will be discharge through a decant orifice structure into a 30' vegetaged filter. 2. Stormwater runoff from this project drains to the Newport River basin. 3. Total Project Area: 9.41 acres 5. How many drainage areas does the project have?_ 4. Project Built Upon Area: 70 % 6. Complete the following information for each drainage area. If there are more than two drainage areas in the project, attach an additional sheet with the information for each area provided in the same format as below. BasmInformation , -� Tut. Drama e Area.1 ..,,.. .g... .. ., "U� Dramage Area?2 Receiving Stream Name Newport River Newport River Receiving Stream Class C C Drainage Area '9-.27 Acres 0.27 Acres Existing Impervious* Area 0 0 Propose Im ervious"Area 6.56 Acres 0.085 % Impervious* Area (total) 69.71 62 Im Rfl> • erviousa,Surface,Area Drama e°Anaxl v ag Y w Dramage°Area2 ........... On -site Buildings .69 Acres 0 Acres On -site Streets .93 Acres .085 Acres On -site Parking 4.94 Acres Acres On -site Sidewalks Other on -site Off -site Total: 6.56 Acres Total: 0.085 Acres " Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas, sidewalks, gravel areas, etc. Form SWU-101 Version 3.99 Page 2 of 4 How was the off -site impervious area listed above derived? IV. DEED RESTRICTIONS AND PROTECTIVE COVENANTS The following italicized deed restrictions and protective covenants are required to be recorded for all subdivisions, outparcels and future development prior to the sale of any lot. If lot sizes vary significantly, a table listing each lot number, size and the allowable built -upon area for each lot must be provided as an attachment. 1. The following covenants are intended to ensure ongoing compliance with state stormwater management permit number SW8 991 202 as issued by the Division of Water Quality. These covenants may not be changed or deleted without the consent of the State. 2. No more than See CAI c chL quare feet of any lot shall be covered by structures or impervious materials. Impervious materials include asphalt, gravel, concrete, brick, stone, slate or similar material but do not include wood decking or the water surface of swimming pools. 3. Swales shall not be filled in, piped, or altered except as necessary to provide driveway crossings. 4. Built -upon area in excess of the permitted amount' requires a state stormwater nunageinent permit modification prior to constriction. 5. All permitted r noff from outparcels or future development shall be directed into the permitted stormwater control system. These connections to the stormwater control system stall be performed in a manner that maintains the integrity and performance of the system as permitted. By your signature below, you certify that the recorded deed restrictions and protective covenants for this project shall include allthe applicable items required above, that the covenants will be binding on all parties and persons claiming under them, that they will run with the land, that the required covenants cannot be changed or deleted without concurrence from the State, and that they will be recorded prior to the sale of any lot. V. SUPPLEMENT FORMS The applicable state stormwater management permit supplement form(s) listed below must be subnutted for each BMP specified for this project. Contact the Stormwater and General Permits Unit at (919) 733-5083 for the status and availability of these forms. Form SWU-102 Wet Detention Basin Supplement Form SWU-103 Infiltration Basin Supplement Form SWU.104 Low Density Supplement Form SWU-105 ..'Curb Outlet System Supplement Form SW U4106 Off -Site System Supplement Form SWIM& Underground Infiltration Trench Supplement Form SWU-108 Neuse River Basin Supplement Form SWU-109 Innovative Best Management Practice Supplement Form SWU-101 Version 3.99 Page 3 of 4 VI. SUBMITTAL REQUIREMENTS Only complete application packages will be accepted and reviewed by the Division of Water Quality (DWQ). A complete package includes all of the items listed below. The complete application package should be submitted to the appropriate DWQ Regional Office. Please indicate that you have provided the following required information by initialing in the space provided next to each item. • Original and one copy of the Stormwater Management Permit Application Form • One copy of the applicable Supplement Form(s) for each BMP • Permit application processing fee of $420 (payable to NCDENR) • Detailed narrative description of stormwater treatment/management • Two copies of plans and specifications, including: - Development/Project name - Engineer and firm -Legend - North arrow - Scale - Revision number & date - Mean high water line - Dimensioned property/project boundary - Location map with named streets or NCSR numbers - Original contours, proposed contours, spot elevations, finished floor elevations - Details of roads, drainage features, collection systems, and stormwater control measures - Wetlands delineated, or a note on plans that none exist - Existing drainage (including off -site), drainage easements, pipe sizes, runoff calculations - Drainage areas delineated - Vegetated buffers (where required) VII. AGENT AUTHORIZATION If you wish to designate authority to another individual or firm so that they may provide information on your behalf, piease complete this section. Designated agent (individual or Mailing Address: City:_ Phone: (' VIII. APPLICANT'S CERTIFICATION State: Fax: ( I) I, (print or type name of person listed in General Information, item 2) DIMI 16 (A 1 0 ` -1 O r certify that the information included on this permit application form is, to the best of my knowledge, correct and that the project will be constructed in conformance with the approved plans, that the required deed restrictions and protective covenants will be recorded, and that the proposed project complies with the requirements of 15A NCAC 21-1.1000. Date: 07—/_ 00 Form SWU-10I Version 3.99 Page 4 of 4 ii'l!/f71011i P E C.T. Clayton, Professional Engineer STORNA L Scott Vinson IU1 E C E 1, V E D March 23, 2000 Environmental Engineer W n7,44.. 127 Cardinal Dr. Ext. Z 4 2M Wilmington, NC 28405 910 395-3900 DWQ PROD 0 Stormwater Project No. SW8 991202 Dear Mr. Vinson: In response to your letter dated March 16, 2000 on the Stormwater Plan for David A. Horton, we have the following response to your comments and are enclosing a set of plans and documents for your final review. 1) As stated in the March 1, 2000 letter, by giving the pond system a two foot deep channel between the forebay and the main pond there is less area being created at the design depth of 6 feet then is allowed. The vast majority of the entire pond must be at the design depth, in this case 6 foot deep. In order to help meet the 3:1 requirement as well as volume and surface area requirements, replace the channel with a wooden baffle stretched out across the pond and relocate the outlet structure to the other corner of the pond. A sketched drawing is included to help with conception. Response: See sheet 1 and 2 of plans for pond layout. 2) Please provide a new drainage map showing the two separate runoff drainage areas. Response: See sheet 1 of plans. 3) Provide calculations for the sand filter design showing that the volume, surface area, and orifice/draw down time requirements have been met. Include P.E. seal and signature Response: See attached calculations. 4) Write out and sign on a separate sheet of paper the Operation & Maintenance agreement for the sand filter. This 0&M must be signed, dated, and notarized just like the O&M for the detention pond. Response: Modified Stormwater Maintenance Plan to include sand filter. 5) Please provide grading or other structure around the sand filter to prevent other runoff from entering the device. The grading given for Lot 13, beside the sand filter, shows the potential for off -site runoff entering the sand filter. Phone: 252 672-0304 2807 NEUSE BLVD., BLDG. 5 Mobile: 252 671-6979 Fax: 252 633-6551 NEW BERN, NC 28562 Home: 910 897-0660 Response: Added curbing on south & west side to prevent off -site drainage into the sand filter. 6) Please revise sheet 2 of 4 of the application to show the two drainage areas. For example the pond would be Drainage Area 1, and the sand filter would be Drainage Area 2. I am also including page 1 of 4 of the detention pond supplement form so that corrections can be made if needed. Response: Modified applications forms. Please review this submittal and should you have questions or comments please advise. Sincerely, C.T. Clayton, P.E. ... cc: David A. Horton Brad L. Suitt file Phone: 252 672-0304 SW8 991202 Mobile: 252 671-6979 Fax: 252 633-6551 2 of 2 Home: 910 897-0660 Phone: 252 672-0304 ctc@cconnect.net Sand Filter Calculations Total Area Proposed Building Area Proposed Roadway/Drainage Area Green Area Sediment Chamber Volume Required Surface Area Required Chamber Provided Height Width Depth Volume Surface Area Sand Filter Chamber Volume Required Surface Area Required Chamber Provided Height Width Depth Volume Surface Area Outlet .T.Clayton, RE�b {/ Fax: 252 633-65511 C.T. Clayton, Professional Engineer Units Symbols & Goveming Equations 0.138 ac TA 0.000 ac BA 0.085 ac PA 0.052 ac GA 46.116 ft' V= 540 ft3 /acre drainage area 30.744 ft2 SA= 360 ftZ /acre 1.500 ft 31.000 ft 1.000 ft 46.500 ft' 31.000 ft' 46.116 ft' V= 540 ft' /acre drainage area 30.744 ftZ SA= 360 ftZ /acre 1.500 ft 31.000 ft 1.000 ft 46.500 ft' 31.000 ft' Area (24 hour drawdown) 0.00876134 sq in A1=(Q/Cd)/(2gh)4.5 where Q=V/time, Cd = 0.60, h=DSD/2 time=86400 seconds (24 hours) Diameter of Orifice (24 hour drawdown) 0.10561859 in D1=2"(A1/PI)^.5 Final Orifice Diameter 4.00 in Hole = 1 Orifice Flow Outlet Time 0.29711635 cfs 17.8269813 cfm 1069.61888 cfh 25670.853 cf day 0.00181139 days Q=CdA'(2gh)^.5 3� a;�_oo Job no. Cad1352 Stormwater Management Revised 03/22/2000 Ter Soott Vinson >o Cloytv�, PE zeoT r¢usc e�w., e�oo. s Nei BEPN, NG 1e6rE From: dee Cornpony Nana: Wilmington Regional Office � aj 6 3 3 - 3— 7 77 Fan 910 350.2004 Pagard, including this Phone: fiats: March 21,2000 Re: Stormwater Pro]. No. SWtl 991202 CC: O For Review X Pismo Convent o Comnoats: David Horton Project. ❑ Hard Copy to Fellow ❑ This is your Original Just wanted to make sure this is everything that you will be requiring. Thanks dee , �oe, Phone: 252 672-0304 uob1le: 252 671.6979 Home: 910 697-0660 Fax: 252 633-6551 Email: ctc@cconnect.net 5TORMWATER MAINTENANCE FLAN for DAVID A. HORTON COMMERCIAL PARK Morehead Township Carteret County North Carolina Im 3, - oo Revised March 20, 2000 TABLE of CONTENTS Narrative....................................................................................................................................................................... 3 5tormwater Pond Maintenance Plan ................. 5and Filter Maintenance Plan ....................................................................... 5 .............................................. I ....... I................ 7 -2- NARRATIVE Project Description The purpose of the project is to construct a stormwater retention pond and to construct a sand filter to serve 9.41 acre Commercial Park. The project is in Morehead Township, Carteret County, North Carolina and is being developed by David A. Horton. The work proposed will include excavation of the stormwater retention pond for the Commercial Park, and construction of a sand filter and its on site storm drainage system. 5ite_12escription See Plan. Adjacent -Property Land use in the vicinity is commercial and residential. The property to the southeast is owned by David A. Horton, all other properties adjoining are owned by others, and will not be affected by the work. Panned_Erosion_and_Sedimentation Control_P_ractices A temporary gravel construction entrance/exit will be installed at the east project entrance. During wet weather it may be necessary to wash vehicle tires at this location. The entrance will be graded so that runoff water will be directed away from proposed roadway. As soon as final grade is reached on the proposed roadway, the subgrade will be stabilized with a 6-inch course of NC DOT standard size ABC stone to prevent erosion and dust during the construction prior to paving. 51opes will be lightly roughened by disking just prior to vegetating. Surface stabilization will be accomplished with vegetation and mulch as specified in the vegetation plan. Roadway base courses will be installed as soon as finished grade is reached. Dust control is not expected to be a problem due to the small area of exposure. Should excessive dust be generated, it will be controlled by sprinkling with water. 5oils The project site soils consists mainly of sand, silt and clay. General The stormwater collection system described will provide the following methods for control of sediments and for removal of pollutants from the developed site runoff. -3- 5tormwater_Pond Collection of all runoff from the site during development of the stormwater retention pond with controlled discharge. 2. Retention of the first one (1) inch of rainfall of runoff on the roadway and proposed parking and building areas into the stormwater retention pond. This runoff will drain over a 2 to 5 day period into the grass -lined Swale before draining into an existing Swale. 3. The retention time for the pond are set at 2.88 days with a total outfall of 8592 of/day from a 2 inch diameter orifice. 4. The stormwater runoff in excess of the first one (1) inch of rainfall will discharge from the stormwater retention pond into a decant orifice structure. The storm pool elevation is set at 23.85' ABV M51- with an additional 11' emergency discharge, at elevation 24.0' adjacent to the existing ditch, as shown on the plan. 5. The project site to be served by the stormwater retention pond and a sand filter (below) as shown on the "5tormwater Management Plan of David A. Horton". 0. No 404 wetlands have been determined to be on this site. 7. 5eeding specifications shall be as specified in the approved Erosion and Sedimentation Control Plan. 5andLFitter. Collection of all runoff from the site during development of the sand filter with controlled discharge. 2. 5and filters work by receiving the first flush of runoff and settling out the heavier sediment in the sediment chamber. Water then flows to, and is spread over the sand bed where pollutants are either trapped or strained out. 3. The retention time for the pond is set at 24 hours with a total outfall of 8592 cf/hr from a 4 inch diameter orifice. -4- MAINTENANCE PLAN 5tormwater Pond The Owner shall maintain the pond during the construction phase of the project and after construction is completed for all routine and non -routine maintenance tasks. The Owner shall also be responsible for the perpetual care of the stormwater retention pond. Conatruction_P_hase All erosion and sediment control practices shall be checked for stability and proper operation following every runoff producing rainfall and in no case less than once every week during construction. All repairs shall be made immediately and shall be in accordance with the approved Erosion and 5edimentation Control Plan. The stormwater retention pond shall be inspected during the construction phase of the project following every runoff producing rainfall and in no case less than once a week. Check the embankment, spillway, outlet, and Swale for erosion damage, and inspect the embankment also for piping and settlement. Make all necessary repairs immediately. Remove all trash and other debris from around the decant orifice structure and from around the pool area. Periodic inspection of the discharge orifice shall assure that the system is not clogged. The retention pond shall be inspected for a build-up of sediment. If and when the sediment layer exceeds 18 inches thick on the average above the design grade, then this sediment shall be removed. At the close of the construction phase of the project, the pond shall be cleaned of excess sediment to the designed grade and begin functioning as stormwater retention pond. All regrading or repairing of the side slopes, seeding, mowing and any and all repairs shall be performed prior to close-out of the construction phase. The grass -lined Swale from pond overflow structure shall be properly inspected and maintained against erosion, weeds, and woody vegetation. All seeded areas shall be maintained to sustain the required vegetation. Any and all bare areas shall be replanted as necessary, with all repairs made immediately. Ma ntenance_Requirements Owner shall be responsible for all routine and non -routine requirements associated with the maintenance of the stormwater retention pond. Upon completion of earth disturbing activities and for 12 months following completion of the work, the owner shall inspect the site following every runoff producing rainfall. A written log shall be maintained of any needed repairs noted at the inspection, the name of the Contractor completing the repairs, and the date such repairs are completed. Routine -Maintenance 1. Mowing. The side -slopes, embankment, buffer area, areas within the fence, areas adjacent to the emergency spillways and the grass -lined swales shall be mowed at least once a month during the main growing season and at least two other times during the year to prevent woody growth and to control weeds. Grass shall be mowed to a "meadow -like" condition and shall be maintained according to 5ection 6.11 Permanent 5eeding of the approved Erosion and 5edimentation Control Plan. -5- 2. Inspections, The stormwater retention pond shall be inspected (at a minimum of) on an annual basis to ensure that the structure operates in the manner originally intended. Additional inspections shall be conducted during wet weather, or times of extreme weather to determine if each pond is functioning properly. Inspection priorities shall include (but not limited to) the following: checking the embankment for any erosion, subsidence, cracking, bare areas in the grass, and tree growth; the condition of the emergency spillway and adjacent ditch; the fence and adjacent planting buffers; the accumulation of sediment; clogging of the decant orifice structure; the adequacy of upstream and downstream channel erosion protection measures including any modifications which have occurred to the contributing watershed, and the pond structure including the stability of the side slopes. Inspections shall be carried out with "As -Built" retention pond plans 3. Debria_and_Litter-Fcmovat. Debris and litter removal from the surface of the pond shall be included as a part of the periodic mowing operation. Particular attention shall be paid to any floating debris around the decant orifice structure, and the structure shall be checked for possible clogging. Any trash found within the area of the pond, ditch, and fence shall be removed and disposed of properly according the County regulations. 4. ErosiorLControl. Corrective measures and repairs shall be done to the pond side slopes, embankment, emergency spillway and grass lined Swale where settlement, slumping, and erosion has occurred. Repair ac necessary. Repair or replace the riprap protecting the channel near the outlet as required to stop the erosion. All repairs shall be done in accordance with the original plans and specifications. 5. Nuisance�-Control. Owner shall maintain the retention pond and adjacent areas so as to control the possible problems of weeds, odors, algae, and insects. Proper maintenance shall take care of most problems except in times of extreme dry weather. Owner shall also use biological control against mosquito's and algae through the use of fish and fat head minnows when possible in lieu of chemical applications. Non-routina-Maintenance 1. 5tructure_Repairr2-and_Replacement. Owner shall replace all deteriorated inlet/outlet works and decant orifice structure when deterioration from use and age causes them to fail and function properly. Owner shall be responsible for Al costs incurred with their replacement. Replacement shall be in accordance with original plans and specifications. 2. 5ediment-Removal. Owner shall be responsible for the removal of excess accumulated sediment in the pond when the storage capacity is significantly reduced from the design capacity due to the properly designed and functioning stormwater retention pond. Owner shall be responsible for all incurred costs of removal and proper disposal of the sediment in accordance with all local, state, and federal regulations. Sediment removal/clean out cycle for stormwater retention pond is recommended on a ten to twenty year cycle. Owner shall every five (5) years measure the depth of sediment above design grade to determine rate of accumulation and to establish a time line for sediment removal. 0 MAINTENANCE PLAN Sand Filter The Owner shall maintain the sand filter during the construction phase of the project and after construction is completed for all routine and non -routine maintenance tasks. The Owner shall also be responsible for the perpetual care of the 5and Filter. Construction-Ehase All erosion and sediment control practices shall be checked for stability and proper operation following every runoff producing rainfall and in no case less than once every week during construction. All repairs shall be made immediately and shall be in accordance with the approved Erosion and Sedimentation Control Plan. The sand filter shall be inspected during the construction phase of the project following every runoff producing rainfall and in no case less than once a week. Check the Sediment Chamber, 5and Filter Chamber, weir spillways, outlet, and Swale for erosion damage. Make all necessary repairs immediately. Remove all trash and other debris. Periodic inspection of the discharge orifice shall assure that the system is not clogged. The 5ediment Chamber shall be inspected for a build-up of sediment. At the close of the construction phase of the project, the sediment chamber shall be cleaned of excess sediment. Ma i ntenan c e_Requirement,o Owner shall be responsible for all routine and non -routine requirements associated with the maintenance of the 5and Filter. Upon completion of earth disturbing activities and for 12 months following completion of the work, the owner shall inspect the site following every runoff producing rainfall. A written log shall be maintained of any needed repairs noted at the inspection, the name of the Contractor completing the repairs, and the date such repairs are completed. Routine Maintenance Regular maintenance is essential to the long-term performance and durability of the sand filter, as it is with all stormwater BMPs. At least once a year the filter must be inspected after a storm to determine if the filter bed is passing the runoff ac expected. Depending mostly on the activities occurring in the drainage area, most filters will show some decreased capacity for filtration after a few years. Maintenance operations must be performed when storms of approximately one inch are not passing through the filter within 24 hours. Maintenance for sand filters consists of removing the first two or three inches of discolored sand, and replacing this with new sand. The sand that has been removed would then be dewatered, if necessary, and then landfilled. At the same time that maintenance is performed on the sand chamber, the sediment chamber should also be pumped and cleaned. It is most likely that the sediment removed from the first chamber will need to be dewatered before it will be accepted at a landfill. -7- I acknowledge and agree by my Signature below that I am responsible for the performance of the maintenance procedures listed above. 1 agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. �. mejumsene z •, Title: Address: Phone: 5ignat Date: 3 `2Z— ©0 I,. v%��'`��/� / /✓/�%l% a Notary Public for the 5tate'off /, m lwl-1 County of �� do hereby certify t t Personally appeared before me this A6d day of and acknowledge the Due execution of the forgoing 5tormwater Maintenance Plan requirements. Witness my hand and official Seal, SEAL My commission expires -8- 5TORMWATER MAINTENANCE PLAN for DAVID A. HORTON COMMERCIAL PARK Morehead Township Carteret County North Carolina Revired M®rrh 20, 2000 -I- TABLE of CONTENT5 Narrative 3 Stormwater Pond Maintenance Plan......................................................................................................................... 5 Sand Filter Maintenance Plan -7- NARRATIVE The purpose of the project Is to construct a stormwater retention pond and to construct a Band filter to serve 9.41 acre Commercial Paric. The project is In Morehead Township, Carteret County, North Carolina and is being developed by David A. Horton. The work proposed will Include excavatlon of the stormwater retention pond for the Commercial Park, and construction of a sand filter and Its on site storm drainage system, See Plan, Land use In the vicinity Is commercial and reeidential. The property to the southeast is owned by David A. Horton, all other properties adjoining are owned by others, and will not be affected by the work. A temporary gravel construction entrance/exit will be Installed at the east project entrance. During wet weather It may be necessary to wash vehicle tires at this location. The entrance will be graded so that runoff water will be directed away from proposed roadway. As soon as final grade Is reached on the proposed roadway, the subgrade will be stabilized with a 6-inch course of NG DOT standard size AM stone to prevent erosion and dust during the conetruavon prior to paving. Slopes will be lightly roughened by disking just prior to vegetating. Surface stabilization will be accomplished with vegetation and mulch as specified in the vegetation plan. Roadway base courses will be installed as Boon as finlshed grade Is reached. Duet control is not expected to be a problem due to the small area of exposure. Should excessive dust be generated, It will be controlled by sprinkling with water. The project site soils consists mainly of sand, alit and clay. The stormwater collection eyetem described will provide the following methods for control of sediments and for removal of pollutants from the developed site runoff. -'A- 1. Collection of all runoff from the site during development of the stormwater retention pond with controlled discharge. 2. Retention of the first one (1) inch of rainfall of runoff on the roadway and proposed parking and building areas into the stormwater retention pond. This runoff will drain over a 2 to 5 day period into the grass -lined Swale before draining into an existing swale. 3. The retention time for the pond are set at 2.65 days with a total outfall of 8592 cf/day from a 2 Inch diameter orifice. 4. The stormwater runoff in excess of the first one (1) inch of rainfall will discharge from the stormwater retention pond into a decant orifice structure. The storm pool elevation is set at 23.85' ABV M51. wlth an additional 11' emergency discharge, at elevation 24,0' adjacent to the existing ditch, as shown on the plan. 5. The project site to be served by the stormwater retention pond and a sand filter (below) as shown on the "Stormwoter Management Plan of David A. Horton". 6. No 404 wetlands have been determined to be on this site. 7. seeding specifications shall be as specified in the approved Eroclon and Sedimentation Control Plan. 1. Collection of all runoff from the site during development of the sand filter with controlled discharge. 2. Sand filters work by receiving the first flush of runoff and settling out the heavier sediment in the sediment chamber. Water then flows to, and is spread overthe sand bed where pollutants are either trapped or strained out. 3. The retention time for the pond is set at less than 24 hours with a total outfall of 940 cf/hr from a 4 inch diameter orifice. -4- MAINTENANCE PLAN 5tormwater Pond The Owner shall malntain the pond during the construction phase of the project and after construction is completed for all routine and non -routine maintenance tasks. The Owner shall also be responsible for the perpetual care of the atormwater retention pond. All erosion and 6MIment control practices shall be checked for stability and proper operation following every runoff producing rainfall and In no case less than once every week during construction. All repairs shall be made Immediately and shall be In accordance with the approved Erosion and Sedimentation Control Plan. The etormwater retention pond shall be Inspected during the construction phase of the project following every runoff producing rainfall and in no case less than once a week. Check the embankment, spillway, outlet, and ewale for erosion damage, and inspect the embankment also for piping and settlement. Make all necessary repairs immediately, Remove all trash and other debris from around the decant orifice structure and from around the pool area. Periodic inspection of the discharge orifice shall assure that the system is not ciogged. The retention pond shall be Inepected for a build-up of sediment. If and when the sediment layer exceeds 18 Inches thick on the average above the design grade, then this sediment shall be removed. At the close of the construction phase of the project, the pond shall be cleaned of excess sediment to the designed grade and begin functioning as storrnwater retention pond. All regrading or repairing of the side slopes, seeding, mowing and any and all repairs shall be performed prior to close-out of the construction phase. The grass -lined Swale from pond overflow structure shall be properly inspected and maintained against erosion, weeds, and woody vegetation. All seeded areas shall be maintained to sustain the required vegetation. Any and all bare areas shall be replanted as necessary, with all repairs made Immediately. Owner shall be responsible for all routine and non -routine requirements associated with the maintenance of The stormwater retention pond. Upon completion of earth disturbing activities and for 12 months following completion of the work, the owner shall inspect the site following every runoff producing rainfall. A written log shall be maintained of any needed repairs noted at the Inspection, the name of the Contractor completing the repairs, and the date such repairs are completed. 1. Mo_Mng. The alde-slopes, embankment, buffer area, areas within the fence, areas adjacent to the emergency spillways and the grass -lined awales shall be mowed at least once a month during the main growing season and at least two other times during the year to prevent woody growth and to control weede. Grass shall be mowed to a "meadow -like' condition and shall be maintained according to 5ection 6.11 Permanent Seeding of the approved Erosion and Seellmentation Control Plan. -5- 2. InsoT ions. The etormwater retention pond shall be Inspected (at a minlmum of) on an annual basis to ensure that the structure operates in the manner originally intended. Additional Inspections shall be conducted during wet weather, or times of extreme weather to determine if each pond is functioning properly. inspection priorities shall include (but not limited to) the following: checking the embankment for any erosion, subeldence, cracking, bare areas in the grass, and tree growth; the condltlon of the emergency spillway and adjacent ditch; the fence and adjacent planting buffers; the accumulation of sediment; clogging of the decant orifice structure; the adequacy of upetream and downstream channel erosion protectlon measures Including any modifications which have occurred to the contributing watershed, and the pond structure including the stability of the side elopee. Inspections shall be carried out with "As -Built" retention pond plane 3. pshriFs amid LiZrAr Removal. Debris and litter removal from the surface of the pond shall be Included as a part of the perlodic mowing operation. Particular attention shall be, paid to any floating debris Around the decant orifice structure, and the structure shall be checked for possible clogging. Any trash found within the area of the pond, ditch, and fence shall be removed and dleposcd of properly according the County regulations. 4. Froslon_.LantcQL Corrective measures and repairs shall be done to the pond side slopes, embankment, emergency spillway and grass limed Swale where settlement, slumping, and erosion has occurred. Repair as necessary. Repair or replace the riprap protecting the channel near the outlet as required to stop the erosion. All repairs shall be done In accordance with the original plane and specifications. 5. Nul�nce Control. Owner shall maintain the retention pond and adjacent areas so as to control the possible problems of weeds, odors, algae, and Insects. Proper maintenance shall take care of most problems except in times of extreme dry weather. Owner shall also use biological control against mosquito's and algae through the use of fish and fat head minnows when possible in lieu of chemical applications. 1. 5tructure gepairs and Replacement Owner shall replace all deteriorated Inletloutlet works and decant orifice structure when deterioration from use and age causes them to fall and function properly. Owner shall be responsible for all costs Incurred with their replacement. Replacement shall be In accordance with original plane and specifications. 2. Sediment Removal. Owner shall be responsible for the removal of excess accumulated sediment in the pond when the storage capacity le eignlflcantly reduced from the design capacity due to the properly designed and functioning stormwater retention pond. Owner shall be responsible for all Incurred costs of removal and proper disposal of the sediment in accordance with all local, state, and federal regulations. 5edlment removal/clean out cycle for etormwater retentlon pond Is recommended on a ten to twenty year cycle. Owner shall every five (5) years measure the depth of eediment above design grade to determine rate of accumulation and to establish a time line for sediment removal. _r. MAINTENANCE PLAN Sand Filter The Owner shall maintain the sand filter during the construction phase of the project and after construction is completed for all routine and non -routine maintenance tasks. The Owner shall also be responsible for the perpetual taro of the Sand Filter. All erosion and sediment control practices shall be checked for stability and proper operation following every runoff producing rainfall and in no case lose than once every week during construction. All repairs shall be made immedlateb and shall be in accordance with the approved Erosion and 5edlmentotion Control Plan. The sand filter shall be Inspected during the construction phase of the project following every runoff producing rainfall and in no case lees than once a week. Check the Sediment Chamber, Sand Filter Chamber, weir spillways, outlet, and swale for erosion damage. Make all necessary repairs Immediately. Remove all trash and other debris. Periodic Inspection of the discharge orifice shall assure that the system Is not clogged. The Sediment Chamber shall be Inspected for a build-up of sediment. At the close of the construction phase of the project, the sediment chamber shall be cleaned of excess sediment. Owner shall be responsible for all routine and non -routine requirements associated with the malntenance of The Sand Filter. Upon completion of earth disturbing activities and for 12 months following completion of the work, the owner shall inspect the site following every runoff producing rainfall. A written log shall be maintained of any needed repairs noted at the Inspection, the name of the Contractor completing the repairs, and the date such repairs are completed. Regular maintenance Is essential to the long-term performance and durability of the sand filter, as it Is with all stormwater 13MPs. At least once a year the filter must be Inspected after a storm to determine If the filter bed is passing the runoff as expected. Depending mostly on the activltles occurring in the drainage area, most filters will show some decreased capacity for filtration after a few years. Maintenance operations must be performed when storms of approximately one Inch are not passing through the filter within 24 hours. Maintenance for sand filters consists of removing the fires two or three Inches of discolored sand, and replacing this with new sand. The sand that has been removed would then be, dewatered, If necessary, and then landfilled. At the same time that maintenance Is performed on the sand chamber, the sediment chamber should also be pumped and cleaned. It Is most Ilkely that the sediment removed from the first chamber will need to be dewatered before It will be accepted at a landfill. .7. Phone: 252 672•0304 oto@000nnect.net Sand Filter Calculations Total Area Proposed Building Area Proposed Roadway/Drainage Area Green Area Sediment Chamber Volume Required Surface Area Required Chamber Provided Height Width Depth Volume Surface Area Sand Filter Chamber Volume Required Surface Area Required Chamber Provided Height Width Depth Volume Surface Area Met Area (24 hour drawdown) C• ` •Clayton, RE Mob Fax: 252 633.65591 C.T. Clayton, Professional Engineer units S1m3bol$ & Govemina Eauadorm 0.138 ac Cd TA 0,000 ac BA 0.085 ac PA 0.052 ac GA 46.116 ft3 V= 540 ft3 /acre drainage area 30.744 ft2 SA- 360 ft2 /acre 1.500 ft 31.000 ft 1.000 ft 46.500 ft3 31.000 ft3 16740.000 ft3 11160.000 ft2 1.500 It 31.000 ft 1.000 ft 46.500 ft3 31.000 ft3 V= 540 ft3 /acre drainage area SA- 360 ft2 /acre 0.00876134 sq in A1=(0/Cd)/(2gh)A.5 where 0=V/time, Cd = 0.60, h=DSDl2 lime=88400 seconds (24 hours) Diameter of Orifice (24 hour drawdown) 0.10561859 in Final Orifice Diameter Orifice Flow Outlet Time 3.75 in Hole = 0.26113742 cfs 15.6682453 cfm 940.094716 cfh 22562.2732 d day 0.00206096 days D1=2'(A1 /PI)^, 5 1 O=CdA'(2gh)A.5 Job no. Cad1352 Stormwater Management Revised 03/20/2000 IIIIIII 07_ SURVEYOR HAS MADE Illrlrl FOR EASEMENTS OR OWNERSHIP TITLE EVI AND CURRENT TITLE IIIa�PI 08. WATER & SEWER SEW IIIM� 09. THERE ARE NO WETLA NOTIFICATION OF RI IIII OF ENGINEERS dated ill I I tcy,+. y p.a E4�lSac,T, EkNERDETEcrNPlurAr 0 INV. 23.0' j - - RCP .... _ P- -- PROP T 7B OSFD 30' PAVCMFNT 63 95 LTER EXTENSION rfll I; ,:" VEGETATED .RLT SEE OETNL \ DECANT ORIFICE �UT-lt "v" A I RMWATE ; S 1n Cvw-SS Jec4. ,&4 \ m D •, A , 1 / f BULKHEAD ^ 1 E LOT 9 I I ' LOT 8 4 I ,� I$ leQs� pft r.t. ,' � _ / I F ESAY NOW OR FORMERLY ' LARRY HOLLER 4 I DEED BOOK 830, PAGE 678 0 — I STRUCTURE 09 -21— E �.V t I DROP ftfT LOT 1 — 1\\ STRUCK i /B R47 2J.� N _ / \ STRUCTURE od -�-, / — 1 / I \ CULVERT \ \ 162• - 3G'• 1' RC . STRUCIUWE zz DROP IV \ \ 37'-30' RCP C711RE /T `( 2z I \ o_2Z / OP MET OP V&FT h /z STRUCTURE p LOT 11 LOT t Q�� ZZ�a + ti � PROJEC ' cAT c eASH 4 16/ \lam 1 0 /� /// N PROPER' I� � STRUCTURE (i� CULVERT TEMPORARY GRA)IEL / r N' R .o \1� \\ %1L-DE-SAC Iti• T IM 2 SI tog T� \Ifi Intl AIIIAft k�S�gER I' i� A - to.s TE — — — — —v — Q I / BE r ROAL)WAY R-2 50' R/W \ I OF —4—Al SECTION A -A NTS _ DESIGN STORAGE SECTION B-B 1 NTS m 23.8 DESIGN STORAGE � FORESAY INV. O 19.D CI,CD !p I Z W Z ,^ F w / w OWNER/DEVELOPER DAVID A. HORTON 128 LITRE NINE DRIVE MOREHEAD CITY. NC 28557 252 444 1355 Cloyton, P. E. C.T. Clayton, Professional Engineer 4W J1 BLVD., BLD8. 5 SHE STORMWATER MANAG PLAN for DAVID A. HORT MOREHEAD TOWNSHIP, CARTERET COUNTY, N I REFERENCE: LOT 13, 14 & PORTION OF L' LITTLE NINE SUBDIVISION, MAP BOOK 18, PA DEED BOOK 843, PAGE 134, & BOOK 846, 1 CARTERET COUNTY REGISTRY. BRAD L. SUITT & ASSC LAND SURVEYING - SITE PLA IEIVV RONMEIN'TAL pygrTNINC - CC•MMERCL NEW BERM, N_C 505 SLAUGHTERHOUSE F'20.5'' t1T If1G rump. W4 O Z JE LEGEND 29 -- ~- —30 EXISTING CONTOUR RR PROPOSED CONTOUR RIPRAP R W . CENTERLINE RIGHT of WAY STORMWATER 5TORMWATER POND BA51N BOTTOM ELEVATION 1G.0 Ft PERMANENT POOL ELEVATION 22.0 ft TEMPORARY POOL ELEVATION 23.8 ft PERMANENT POOL SURFACE AREA DRAINAGE AREA IMPERVIOUS AREA PERMANENT POOL VOLUME DESIGN STORAGE VOLUME FOREBAY VOLUME SA/DA USED DIAMETER OF ORIFICE DESIGN TSS REMOVAL 12550= sq ft 9.41, acres G.5G acres 45153 * cu Ft 248371 cu ft 9433= cu ft 2.9 1 MOLE 2' 85Z SKEET 1 of 2 GRAPHIC SCALE m a 12D Y« ( D( rat ) i inch = 00 tL CAD1352 i MODIFIED PER NCDENR LETTER DATED 3-16-00 1 dee MODIFIED PER NCOENR LETTER DATED 3-1-00 1 dee MODIFIED PER NCDENR LETTER DATED 1-18-00 1 dee DESCRIPPON BY a GENERAL LEGEND 01. 0 = EXISTING IRON PIPE 02. O = NEW IRON PIPE MAP AWLe, PA01 07. 03. R/W = RIGHT OF WAY 04. SQ.FT. = SQUARE FEET 05. UTILITY POLE 06. # = AERIAL LIGHT 07. N = EXISTING CONCRETE MONUMENT 08_ C/L = EXISTING CENTERLINE OF PAVEMENT 09. & = P.K. NAIL 10. P/L = PROPERTY LINE. SAND FILTER NTS jlj+ State of North Carolina Department of Environment and Natural Resources Wilmington Regional Office James B. Hunt, Jr., Governor Bill Holman, Secretary Division of Water Quality March 16, 2000 Mr. David Horton, Owner 128 Little Nine Drive Morehead City, NC 28557 �j •le'.•f W Subject: ACKNOWLEDGMENT OF RECEIPT AND REQUEST FOR ADDITIONAL INFORMATION Stormwater Project No. SW8 991202 David A. Horton Carteret County Dear Mr. Horton: The Wilmington Regional Office received a Stormwater Management Permit Application for David A. Horton on March 15, 2000. A preliminary review of that information has determined that the application is not complete. The following information is needed to continue the stormwater review: . I. As stated in the March 1, 2000 letter, by giving the pond system a two foot deep channel between the forebay and the main pond there is less area being created at the design depth of 6 feet then is allowed. The vast majority of the entire pond must be at the design depth, in this case 6 foot deep. In order to help meet the 3:1 requirement as well as volume and surface area requirements, replace the channel with a wooden baffle stretched out across the pond and relocate the outlet structure to the other corner of the pond. A sketched drawing is included to help with conception. .i2. Please provide a new drainage map showing the two seperate runoff drainage areas. 3. Provide calculations for the sand filter design showing that the volume, surface area, and orifice/draw down time requirements have been met. Include P.E. seal and signature. 114. Write out and sign on a separate sheet of paper the Operation & Maintenance agreement for the sand filter. This O&M must be signed, dated, and notarized just like the O&M for the detention pond. --5. Please provide grading or other structure around the sand filter to prevent other runoff from entering the device. The grading given for Lot 13, beside the sand filter, shows the potential for off -site runoff entering the sand filter. -/6. Please revise sheet 2 of 4 of the application to show the two drainage areas. For example the pond would be Drainage Area 1, and the sand filter would be Drainage Area 2. I am also including page 1 of 4 of the detention pond supplement form -so that corrections can be made if needed. 127 Cardinal Dr. Ext., Wilmington, North Carolina 29405 Telephone 910-395-3900 FAX 910-350-2004 An Equal Opportunity Affirmative Action Employer 50% recycled/10 % post -consumer paper Mr. Horton March 16. 2000 Stormwater Project No. SW8 991202 Please note that this request for additional information is in response to a preliminary review. The requested information should be received by this Office prior to April 16, 2000, or the application will be returned as incomplete. The return of a project will necessitate resubmittal of all required items, including the application fee. If you need additional time to submit the information, please mail or fax your request for a time extension to the Division at the address and fax number at the bottom of this letter. The request must indicate the date by which you expect to submit the required information. The Division is allowed 90 days from the receipt of a completed application to issue the permit. The construction of any impervious. surfaces, other than a construction entrance under an approved Sedimentation Erosion Control Plan, is a violation ofNCGS 143-215.1 and is subject to enforcement action pursuant to NCGS 143-215.6A. Please reference the State assigned project number on all correspondence. Any original documents that need to be revised have been sent to the engineer or agent. All original documents must be returned or new originals must be provided. Copies are not acceptable. If you have any questions concerning this matter please feel free to call me at (910) 395-3900. Sincerely, 42 Scott Vinson Environmental Engineer RSSlsav: S:\WQS\STORMWAT\ADDINFO\991202.MAR cc: Wilmington Regional Office C.T. Clayton P.E. -6'48' 63 95 — = — — — — — 98 VEGETATED FILTER N 03_0to — — — — — SEE DETAIL -24, - _ — EDPAS AI 0. �,`\ SECURITY FENCE 1 I [ \ / by OWNER DECANT K 7Q �%Vw 1 " f _. )1 ORIFICE 11 1 WOOa 6-fIt I -_� STRUCTURE LOT 7 , 1� V cl.a� I foWATER' ° A 2;.4G I \� IJ Ian [0rK4 o FZ ae. / RM LOT 8 tO I (P cl¢ e� NV. 173E I Q ^QO °�Sti b 1 �26 1 3� NOW OR FORMERLY �3 2� LARRY HOLLER 4�2 0' OT 8 I=� 'I I i FOP.EM 18 a ^� DEED BOOK 830, PAGE 678 O ro _ ry 01 1 1 STRUCTURE B9 o_ m' 1 —24- —76.4'01L — 1 ` I I IDROP INLET\ I-77--PA- LOT LOT 1Y 7/STRUCTUR p8 RIM 23.5 CUL/ERT� �- ZQ DRAIN EASE. ///P' I I i 1 INS I9:6— — � \ li 5 }f STRUCTURE CULVERT _ _ _ / STRUCTURE R J 1 I0 DRAt. EAE$E, I \ 782' - 3G' RCP . 0.27. STRUCTURE #5 7'- 4' 1 V 37R30N ILET RCP TRUCTURE p7 �RDP INLET J' \DROP ,INLET //Z// 1 STRICTURE y3 LOT 11 ` LOT 1 L INV. 142 CA7BASIN STRUCTURE III 1 I 1 BASIN ✓ CATCH BASINSTRUCTUY CULVERT R� \ I 1 1 TEMPORARY GRAVEL �C L-DE-SAC I _ a 11 / R .0' -1+02_ .�- y DRAINAGE EASEMENT I - I V. 20.4 --w v V __ V v '— V rt 11 ROADWAY R-2 51_R-4---i--_ + ROJECT ROPERTY LINE cr I Q/ NOTE: C IMPERVIOUS AF SHALL BE 807 THE LOTS WILL THAT ALL IMPS BE DIRECTED OR TOWARD TF ALL ROOF DRA DIRECTED SO i BY THE POND. lltftl�� o Clpyta�, P.E. C.7. Clayton, Professional Engineer TO: Scott Vinson NCDENR Wilmington Regional Office 127 Cardinal Drive Ext. Wilmington, NC 28405-3845 WE ARE SENDING: x 'Originals ❑ Specifications LETTER OF TRANSMITTAL DATE: March 7, 2000 PROJECT NO: Cad 1 352 TASK NO: 0001 RE: David A. Horton Stormwater Project No. SW8991202 TRANSMITTAL NO: 1 PAGE 1 OF 1 x Prints ❑ Calculations ❑ Shop Drawings ❑ Samples ❑ Other - Quantity Drawing No. Rev. Description Status 1 Revised partial Application, Stormwater Management 2 Cad1352 Copies of Stormwater Management Plan nD E C E@ N E MAR 15- DINO Paa a Issue Status Code: A. Preliminary B. Fabrication Only C. For Information D. Bid E. Construction F. For Review & Comments G. For Approval H. See Remarks REMARKS: 2807 NEUSE BLVD. BLDG. k5 NEW BEBN, NG 28562 252 672-0304 FAX 252 633-6551 cc: Brad L. Suitt David A. Horton ,Signed e C.T. Cla , P. . DAMy DocumentsUransCad1352sw2.doc CT C.(r -4o 1 SNWVA Act+ mt"t,(-4,j 14%,�4- si�ad) 1 n4wj�A 48-�. 3,7 SCA`{h6...f •IIiw�CY1G�'�M�MM� r5ycc. UPI. /�D.DdS94ci�5"t1J'�� = y(o. j -pf3 re?. mot, $,a:/C.oBS'l�.�C36�+�)= 3a,7`I'F'�la►.in. VD1. Crjowe,. VOA �� ; r4sA,Val. pA Ixk to 2l.. KA . v A` 1" � 2 Nn. Gt =CA 2 h ZV'5) State of North Carolina Department of Environment and Natural Resources Wilmington Regional Office James B. Hunt, Jr., Governor Bill Holman, Secretary Division of Water Quality March 1, 2000 Mr. David A. Horton, Owner 128 Little Nine Dr. Morehead City, NC 28557 1� Ohl N CD NcR CAROLMA DERARTMENr OF ENVIRONMENT AND NATURAL RESOURCES Subject: ACKNOWLEDGMENT OF RECEIPT AND REQUEST FOR ADDITIONAL INFORMATION Stormwater Project No. S W 8 991202 David A. Horton Carteret County Dear Mr. Horton: The Wilmington Regional Office received a Stormwater Management Permit Application for David A. Horton on February 3, 2000. A preliminary review of that information has determined that the application is not complete. The following information is needed to continue the stormwater review: The forebay has been redesigned to be approximately 28% of the permanent pool volume. This is a little bit more than what is allowed. Please try to design the forebay to be in a range between 19-22 % of the permanent pool volume of 41,308 cu.ft. By giving the pond system a two foot deep channel between the forebay and the main pond there is less area being created at the design depth of 6 feet then is recommended. The two new baffle walls that have been proposed can be spread apart a little and dug down 6 feet deep. If this can not be done due to the excessive loss of the surface area and volume due to the earthen berm, then timber bulkhead type berms are recommended. There is about 120 feet of the entrance road not being collected and treated by the pond. In high density developments, all new impervious surfaces are to drain to an engineered designed treatment system. That bit of new impervious within the right-of-way of Little Nine Drive may be allowed to drain away from the project site. 127 Cardinal Dr. Ext., Wilmington, North Carolina 28405 Telephone 910-395-3900 FAX 910-350-2004 An Equal Opportunity Affirmative Action Employer 50% recycled/10% post -consumer paper Mr. Horton March 1, 2000 Stormwater Project No. SW8 991202 Please note that this request for additional information is in response to a preliminary review. The requested information should be received by this Office prior to April 1, 2000, or the application will be returned as incomplete. The return of a project will necessitate resubmittal of all required items, including the application fee. If you need additional time to submit the information, please mail or fax your request for a time extension to the Division at the address and fax number at the bottom of this letter. The request must indicate the date by which you expect to submit the required information. The Division is allowed 90 days from the receipt of a completed application to issue the permit. The construction of any impervious surfaces, other than a construction entrance under an approved Sedimentation Erosion Control Plan, is a violation ofNCGS 143-215.1 and is subject to enforcement action pursuant to NCGS 143-215.6A. Please reference the State assigned project number on all correspondence. Any original documents that need to be revised have been sent to the engineer or agent. All original documents must be returned or new originals must be provided. Copies are not acceptable. If you have any questions concerning this matter please feel free to call me at (910) 395-3900. Sincerely, Scott Vinson Environmental Engineer RSS/sav: S:\WQS\STORMWAT\ADDINFO\991202.MAR cc: Wilmington Regional Office C.T. Clayton, P.E. OC74CIayton, Professional Engineer Scott Vinson Environmental Engineer 127 Cardinal Dr. Ext. Wilmington, NC 28405 910 395-3900 Stormwater Project No. SW8 991202 Dear Mr. Vinson: RECEIVED FEB 0 8 2000 BY:----- February 2, 2000 In response to your letter dated January 18, 2000 on the Stormwater Plan for David A. Horton, we have the following response to your comments and are enclosing a set of plans and documents for your final review. 1) Section III. numbers 2 and 6 need to be filled in completely. For #6 on page 2 of 4 please fill in the receiving stream name and if you can not find the classification for the stream let me know and I will find it on your behalf. I am returning the 4 page application and the 4 page supplement form for needed modifications. Response: River Basin, Receiving, Stream and Receiving Stream Class are listed. 2) Please fill in Section IV. #2 on page 3 of 4 of the application. These deed restrictions and protective covenants must be complete and recorded prior to the sale/construction of any lot. From what is given on the application and plans, there seems to be approximately 16,350 square feet of impervious surface per each of the 15 buildable lots. Please verify and fill in the deed restriction blank. Response: David A. Horton response attached. 3) If Mr. C.T. Clayton and/or Brad Suitt & Assoc., P.A. will be resubmitting any information on your behalf, please fill in their names under Section VII. on page 4 of 4. Response: Not applicable. 4) On page 3 of 4 of the Wet Detention Basin Supplement form, please correct the sediment removal benchmarks from "elevations" to "depths" below the permanent pool elevation of 22.0. Response: Changes made on page 3 of 4 of the Wet Detention Basin Supplement form. 5) Please clearly define the property/project lines for the subdivision on the plans. Phone: 252 672-0304 - 2807 NEUSE BLVD., BLDG. 5 Mobile: 252 671-6979 Fax: 252 633-6551 NEW BERN,NC 28562 Home: 910 897-0660 6-4000141"VA, P.E. Response: See plan. Property is bolder, labeled and put in legend. 6) Please delineate the drainage area for the pond, all impervious areas are to be included. If the layout of each lot has not been decided yet, that please note on the plans that the lots will be graded such that all impervious runoff will be directed toward the street/pond. Note that all roof drains are included and must be directed so as to be picked up by the pond. Response: See note on sheet 1 of 2, Stormwater Management Plan for response on impervious areas. We have delineated with a marker the pond drainage area on sheet 1 of 2. 7) Please dimension the permanent pool of the pond on the plans. Response: See sheet 1 of 2, Stormwater Management Plan. 8) Please provide the vegetated filter required for ponds designed for 8596 TSS removal. These filters are not to be simply connector ditches and they cannot have any other water flowing through them other that what is coming from the pond. Please also provide a detail of the vegetated filter as well . as the calculations needed to show the design width of the filter will have non erosive flow. The filter will also need to have the permanent grassed vegetation to be used specified. Note that these filters are to be designed so that the only time there is standing water in them should be when the pond is draining. I am including a sample detail of a vegetated filter for your reference. The filter should be at least 30 feet in length and have a flow spreader mechanism. Response: See sheet 1 of 2, Stormwater Management Plan and sheet 2 of 2 for detail. 9) The 6:1 vegetative shelf should be around the main pond only. I have enclosed a pond section to help show it. Response: See sheet 1 of 2, Stormwater Management Plan and sheet 2 of 2 for detail. 10) Please raise the southern end of the fiorebay weir up to at least 1 foot below the permanent pool elevation, i.e. 21.00 feet MSL. Response: See sheet 1 of 2, Stormwater Management Plan. Modified fiorebay and weir. 11) The required 3:1 length : width ration for the pond has not been meet, please correct. Response: See sheet 1 of 2, Stormwater Management Plan. Modified Pond. Phone: 252 672-0304 SW8 991202 Mobile: 252 671-6979 Fax: 252 633-6551 2 of 3 Home: 910 897-0660 "Ov"'n, P. E. .. . � 6 12) Currently the forebay is only holding approximately 12% of the permanent pool volume. Please increase the volume of the forebay to hold approximately 20% of the total permanent pool volume. Response: See sheet 1 of 2, Stormwater Management Plan. Modified forebay and weir. 13) Please reference the project number above on all correspondence. Response: Project number is referenced on correspondence. Please review this submittal and should you have questions or comments please advise. Sincerely, C.T. Clayton, P.E. 4 cc: David A. Horton Brad L. Suitt file Phone: 252 672-0304 SW8 991202 Mobile: 252 671-6979 Fax: 252 633-6551 3 of 3 Home: 910 897-0660 ^� Phone: 252 672-0304 C Clayton, R Mobfax: 252 633-6551 ile: 252 671-6979 ctc@cconnect.net C.T. Clayton, Professional Engineer Pond Calculations Units Symbols & Governing Equations Total Site Area 9.41 ac TA Proposed Building Area 0.69 ac BA Proposed Parking Area 5.87 ac PA Green Area 2.85 ac GA Proposed Pond Depth Percent Impervious 69.71 % Surface Area/Drainage Area % 2.9 % Based on 75% Impervious Permanent Pool Surface Area Req'd 11884.60 sq ft Approximate runoff volume for 1" Storm 24811.30 cu ft Permanent Pool Surface Area Provided 12550.39 sq ft Surface Area 2' Above P.P. Surface 15335.29 sq ft Approx. Design Storage Depth Req'd 1.78 ft Permanent Pool Elevation 22.00 ft Design Storage Elevation 23.80 ft Top of Bank Elevation 25.00 ft Bottom Elevation 16.00 ft Design Storage Depth Provided 1.80 ft Design Pool Surface Area 15046.62 sq ft Design Storage Provided 24837.31 cu ft �ECEIVED FEB O 3.2000 DWQ PROD # (TA-GA)-100/rA SA/DA (from Chart 3, 85% TSS removal) SA/DA'TA'43560/100 V=[(BA'1)+(PA'.95)+(GA'.2)]43560/12 PSA (from CAD) SA2 (from CAD) DSD=[2/(PSA+SA2)]V PPE=(from Site Plan) OSE=(from Site Plan) (from Site Plan) (from Site Plan) DSDP=DS-PP DPSA (from CAD) DS=DSDP'(PSA+DPSA)/2 Job no. Cad1352 Stormwater Management Revised 01/25/2000 / 64 ile: 252 671-6979 �+ Phone: 252 672-0304 C T�Claytoni RE Fax: 252 633-65511 J ctc@cconnect.net C.T. Clayton, Professional Engineer Drawdown Outlet Size Area (2 day drawdown) 4.5523954 sq in A2=(Q/Cd)/(2gh)A.5 where Q=V/time, Cd = 0.60, h=DSD/2 time=172800 seconds (2 days) Diameter of Orifice (2 day drawdown) 2.40754851 in D2=2*(A2/PI)A.5 Area (5 day drawdown) 1.82095816 sq in A5=(Q/Cd)/(2gh)A.5 where Q=V/time, Cal = .60, h=DSD/2 time=432000 seconds (5 days) Diameter of Orifice (5 day drawdown) 1.52266738 in D5=2*(A5/PI)A.5 Final Orifice Diameter 2.00 in Hole = 1 Orifice Flow 0.09908678 cfs Q=CdA*(2gh)A.5 5.94520702 cfm 356.712421 cfh 8561.0981 cf day Outlet Time 2.89814492 days Riser Size Storm Runoff Q = Q=CAi C = 0.697139246 A = 9.41 55.9777639 cfs i = 7.00 10 year 83.9666459 cfs i = 10.50 100 year Weir Discharge 84.213479 cfs Q = CwLH34 Cw = 3.33 L = pi*d L = pi*40" L = 10.47197551 H = 1.80 40" Riser outlet will handle a 100 year storm with Pond water level rise less than 1.80 feet Job no. Cad1352 Stormwater Management Revised 01/25/2000 SEDCAD 4 for Windows -Copyright 1998 Pamela J. Schwab Cldl Software Design 1 Sediment Basin Phase 2 Revised 01-25-00 for Vegetated Filter Calculations FEB O 3.2000 DWO PROJ # M C.T. Clayton 2807 Neuse Blvd., Bldg. 5 New Bem, NC 28562 Phone: 252 672-0304 Email: ctc@cconnect.net eE;L rj;;)5 _` R-' z-00 Filename: Cad1352-31.sc4 Printed 01-25-2000 SEDCAD 4 for Windows Coprght 1998 Pamela J. Schwab Civil Software Design Genera/ Information Storm Information: Storm Type: NRCS Type III Design Storm: 25 yr - 24 hr Rainfall Depth: 8.500 inches Filename: Cad1352-31.sc4 Printed 01-25-2000 SEDCAD 4 for Windows Copyright 1996 Pamela J. Schwab Civil Software Design Structure Networking; Type Stru # (Flaws into) Stru # Musk. K (hrs) Musk. X Description Pond I #1 ==> #2 0.000 0.000 ! Catch Basin Culvert #2 =_> #3 0.000 0.000 Pond #3 =_> #4 0.000 0.000 Catch Basin Culvert #4 =_> #5 0.000 0.0001 Pond F#5 =_> #6 0.000 0.000 Drop Inlet Culvert I #6 =_> #7 0.000 0.000 Pond #7 =_> #8 0.000 0.000 Drop Inlet Culvert #8 =_> #9 0.000 0.000 Pond #9 =_> #10 I 0.000 0.000 Sediment Basin Channel #10 =_> End I 0.000 0.000 Vegetated filter 1¢ #1 Pond #2 Culvert #3 Pond #4 Culvert #5 Pond #6 Culvert 4 #7 Pond #8 Culvert 41 #9 Pond #10 Chan? Filename: Cad1352-31.sc4 Printed 01-25-2000 SEDCAD 4 for Windows Copyright 1998 Pamela J. Schwab Civil Software Design 4 Structure Summary; Immediate Total Peak Total Contributing Contributing Discharge Runoff Area Area Volume (ac) (ac) (cfs) (ac-R) In 11.22 2.09 #1 3.295 3.295 Out 11.21 2.09 #2 0.000 3.295 11.21 2.09 In 21.68 4.05 #3 3.069 6.364 Out 21.67 4.05 #4 0.000 6.364 21.67 4.05 In 23.98 4.48 #5 0.680 7.044 Out 23.97 4.48 #6 0.000 7.044 23.97 4.48 In 26.68 4.98 #7 0.797 7.841 Out 26.67 4.98 #8 0.000 7.841 26.67 4.98 In - 26.67 4.98 #9 0.000 7.841 Out 3.99 4.98 #10 0.000 7.841 3.99 4.98 Filename: Cad1352-31.so4 Printed 01-25-2000 SEDCAD 4 for Windows Copynght 1998 Pamela J. Schwab Civil Software Design Catch Basin Pond Inputs: Structure Detail; Initial Pool Elev: 0.10 Initial Pool: 0.00 ac-ft Straight Pipe Barrel Barrel Entrance Tailwater Barrel Manning's Spillway Diameter Length Loss Depth Slope (%) n Elev (in) (ft) � Coefficient (R) 24.00 31.00 0.20 1 0.0160 0.101 0.20 0.00 Pond Results: Peak Elevation: 1.93 Dewater Time: 0.49 days Dewatenng time is calculated from peak stage to lowest spillway Elevation -Capacity -Discharge Table Elevation Area (ac) Capacity (ac-ft) Discharge (Cfs) Dewater Time (hrs) 0.00 0.000 0.000 0.000 0.10 0.000 0.000 0.000 Spillway #1 0.50 0.000 0.000 1.577 10.50 1.00 0.000 0.000 4.442 1.05 1.50 0.000 0.000 7.191 0.05 1.93 0.000 0.000 11.208 0.05 Peak Stage 2.00 0.000 0.000 11.880 2.50 0.000 0.000 15.749 3.00 0.000 0.000 18.874 3.50 0.000 0.000 21.862 3.85 0.000 0.000 23.736 Detailed Discharge Table Filename: Cad1352-31.sc4 Printed 01-25-2000 SEDCAD 4 for Windows Copyright 1998 Pamela J. Schwab Civil Software Design 0 Elevation Straight Pipe (cfs) Combined Total Discharge (cfs) 0.00 0.000 0.000 0.10 0.000 0.000 0.50 (1)>1.577 1.577 1.00 (1)>4.442 4.442 1.50 (1)>7.191 7.191 2.00 (1)>11.880 11.880 2.50 (3)>15.749 15.749 3.00 (5)>18.874 18.874 3.50 (5)>21.862 21.862 3.85 (5)>23.736 23.736 Structure #2 (Culvert% Culvert Inputs: Max. Tailwater Entrance Length (ft) Slope (%) Manning's n Headwater Loss Coef. (ft) (ft) (Ke) 31.00 0.20 0.0160 2.00 0.00 0.20 Culvert Results: Design Discharge = 11.21 cfs Minimum pipe diameter: 1 - 24 inch pipe(s) required Structure #3 (Ponds Catch Basin Pond Inputs: Initial Pool Elev: 0.10 Initial Pool: 0.00 ac-ft Straight Pipe Barrel Barrel Entrance Tailwater Barrel Manning's Spillway Diameter Length Loss Depth Slope (%) n Elev (in) (ft) Coefficient (ft) 30.00 37.00 0.20 0.0160 0.101 0.20 0.00 Pond Results: Peak Elevation: 2.54 Dewater Time: 0.49 days Dewatenng time is calculated from peak stage to lowest spillway Filename: Cad1352-31.sc4 Printed 01-25-2000 SEDCAD 4 for Windows Copyright 1998 Pamela J. Scnwab Civil Software Design 7 Elevation -Capacity -Discharge Table Elevation Area (ac) Capacity (ac-ft) Discharge (cfs) Dewater Time (hrs) 0.00 0.000 0.000 0.000 0.10 0.000 0.000 0.000 Spillway #1 0.50 0.000 0.000 1.969 9.05 1.00 0.000 0.000 6.035 2.45 1.50 0.000 0.000 9.827 0.10 2.00 0.000 0.000 14.388 2.50 0.000 0.000 21.210 2.54 0.000 0.000 21.667 0.05 Peak Stage 3.00 0.000 0.000 27.174 3.50 0.000 0.000 30.885 3.85 0.000 0.000 34.094 Detailed Discharge Table Elevation Straight Pipe (cfs) Combined Total Discharge (cfS) 0.00 0.000 0.000 0.10 0.000 0.000 0.50 (1)>1.969 1.969 1.00 (1)>6.035 6.035 1.50 (1)>9.827 9.827 2.00 (1)>14.388 14.388 2.50 (1)>21.210 21.210 3.00 (2)>27.174 27.174 3.50 (5)>30.885 30.885 3.85 (5)>34.094 34.094 Structure #4 (�LlvertJ Culvert Inputs: Max. Tailwa[er Entrance Length (ft) Slope (%) Manning's n Headwater Loss Coef. (ft) (ft) (Ke) 37.00 0.20 0.0160 2.50 0.00 0.20 Culvert Results: Design Discharge = 21.67 cfs Minimum pipe diameter: 1 - 30 inch pipe(s) required Filename: Cad1352-31.sc4 Printed 01-25-2000 SEDCAD 4 for Windows Copyright 1998 Pamela J. Schwab Civil Software Design Drop Inlet Pond Inputs: Initial Pool Elev: 0.10 Initial Pool: 0.00 ac-R Straight Pipe Barrel Barrel Entrance Tailwater Barrel Manning's Spillway Diameter Length Loss Depth Slope (%) . n Elev (in) (R) Coefficient (R) 36.00 182.00 0.201 0.0160 0.101 0.20 0.00 Pond Results: Peak Elevation: 2.58 Dewater Time: 0.49 days Dewatedng t/me is calculated from peak stage to lowest -spillway Elevation -Capacity -Discharge Table Elevation Area (ac) Capacity (ac-R) Discharge (cfs) Dewater Time (hrs) 0.00 0.000 0.000 0.000 0.10 0.000 0.000 0.000 Spillway #1 0.50 0.000 0.000 4.685 11.10 1.00 0.000 0.000 8.965 0.50 1.50 0.000 0.000 12.654 2.00 0.000 0.000 16.166 2.50 0.000 0.000 22.664 2.58 0.000 0.000 23.971 0.05 Peak Stage 3.00 0.000 0.000 30.414 3.50 0.000 0.000 36.973 3.90 0.000 0.000 40.307 Detailed Discharge Table Filename: Cadl352-31.sc4 Printed 01-25-2000 SEDCAD 4 for Windows Copyright 1998 Pamela J. Schwab Civil Software Design 0 Elevation Straight Pipe (ds) Combined Total Discharge WS) 0.00 0.000 0.000 0.10 0.000 0.000 0.50 (1)>4.685 4.685 1.00 (1)>8.965 8.965 1.50 (1)>12.654 12.654 2.00 (1)>16.166 16.166 2.50 (1)>22.664 22.664 3.00 (1)>30.414 30.414 3.50 (2)>36.973 36.973 3.90 (6)>40.307 40.307 Structure #6 (Culvert Culvert Inputs: Max. Tailwater Entrance Length (ft) Slope (%) Manning's n Headwater Loss Coef. (ft) (R) (Ke) 182.00 0.20 0.0160 2.50 0.00 0.20 Culvert Results: Design Discharge = 23.97 cfs Minimum pipe diameter: 1 - 36 inch pipe(s) required Structure #7 692nd1 Drop Inlet Pond Inputs: Initial Pool Elev: 0.10 Initial Pool: 0.00 ac-R Straight Pive Barrel Barrel Entrance Tailwater Barrel Manning's Spillway Diameter Length Loss Depth Slope (%) n Elev (in) (ft) Coefficient (R)' 36.00 128.00 0.20 0.0160 0.101 0.20 0.00 Pond Results: Peak Elevation: 2.71 Dewater Time: 0.49 days Dewatering time is calculated from peak stage to lowest spillway Filename: Cad135231.sc4 Printed 01-25-2000 SEDCAD 4 for Windows Copynght 1998 Pamela J. Schwab Civil Software Design 10 Elevation -Capacity -Discharge Table Elevation Area (ac) Capacity (ac-ft) Discharge (crs) Dewater Time (hrs) 0.00 0.000 0.000 0.000 0.10 0.000 0.000 0.000 Spillway #1 0.50 0.000 0.000 3.811 10.60 1.00 0.000 0.000 8.528 0.95 1.50 0.000 0.000 12.724 0.05 2.00 0.000 0.000 16.432 2.50 0.000 0.000 23.298 2.71 0.000 0.000 26.670 0.05 Peak Stage 3.00 0.000 0.000 31.390 3.50 0.000 0.000 38.848 4.00 0.000 0.000 44.547 4.50 0.000 0.000 51.007 5.00 0.000 0.000 56.745 5.50 0.000 0.000 61.945 5.60 0.000 0.000 62.937 Detailed Discharge Table Elevation Straight Pipe (cPs) Combined Total Discharge (ffs) 0.00 0.000 0.000 0.10 0.000 0.000 0.50 (1)>3.811 3.811 1.00 (1)>8.528 8.528 1.50 (1)>12.724 12.724 2.00 (1)>16.432 16.432 2.50 (1)>23.298 23.298 3.00 (1)>31.390 31.390 3.50 (2)>38.848 38.848 4.00 (6)>44.547 44.547 4.50 (6)>51.007 51.007 5.00 (6)>56.745 56.745 5.50 (6)>61.945 61.945 5.60 (6)>62.937 62.937 Culvert Inputs: Rename : Cad1352-31.sc4 Printed 01-25-2000 SEDCAD 4 for Windows Copyright 1998 Pamela J. Schwab CiNI Software Design Max. Tailwater Entrance Length (ft) Slope (%) Manning's n Headwater ft Loss Coef. (ft) () (Ke) 126.00 0.20 0.0160 3.00 0.00 0.20 Culvert Results: Design Discharge = 26.67 cfs - Minimum pipe diameter: 1 - 36 inch pipe(s) required Structure #9 "nd1 Sediment Basin Pond Inputs: Initial Pool Elev: 7.80 Initial Pool: 0.00 ac-R Perforated Riser Riser Riser Height Diameter Barrel Barrel Barrel Slope Number Of (ft) Diameter u Manning's n Spillway Elev Holes per Length (ft) (/o) (in) (in) Elev 40.00 7.801 6.00 1.00 45.00 0.0140 7.90 6 Pond Results: Peak Elevation: 15.10 Dewater Time: 0.85 days Dewatedng time is calculated from peak stage to lowest spillway Elevation -Capacity -Discharge Table Elevation Area (ac) Capacity (ac-ft) Discharge Dewater Time (cfs) (hrs) 0.00 0.000 0.000 0.000 0.50 0.001 0.000 0.000 1.00 0.004 0.001 0.000 1.50 0.010 0.005 0.000 2.00 0.017 0.012 0.000 2.50 0.027 0.022 0.000 3.00 0.039 0.039 0.000 3.50 0.053 0.062 0.000 4.00 0.069 0.092 0.000 4.50 0.087 0.131 0.000 5.00 0.107 0.179 - 0.000 5.50 0.130 0.238 0.000 Filename: Cad1352-31.so4 Printed 01-25-2000 �S SEDCAD 4 for Windows Copyright 1998 Pamela J. Schwab Civil Software Design 12 Elevation Area (ac) Capacity (ac-ft) Discharge (cgs) Dewater Time (hrs) 6.00 0.155 0.309 0.000 6.50 0.181 0.393 0.000 7.00 0.210 0.491 0.000 7.50 0.241 0.604 0.000 8.00 0.275 0.733 1.027 8.10 8.50 0.310 0.879 2.912 0.95 8.90 0.340 1.009 2.977 Detailed Discharge Table Elevation Pelf. Riser (cfs) Combined Total Discharge (cfs) 0.00 0.000 0.000 0.50 0.000 0.000 1.00 0.000 0.000 1.50 0.000 0.000 2.00 0.000 0.000 2.50 0.000 0.000 3.00 0.000 0.000 3.50 0.000 0.000 4.00 0.000 0.000 4.50 0.000 0.000 5.00 0.000 0.000 5.50 0.000 0.000 6.00 0.000 0.000 6.50 0.000 0.000 7.00 0.000 0.000 7.50 0.000 0.000 8.00 1.027 1.027 8.50 2.912 2.912 8.90 2.977 2.977 Structure #10 (yeaetated Channel Vegetated filter Parabolic Vegetated Channel Inputs: Material: Tall fescue Filename: Cad1352-31.sc4 Printed 01-26-2000 SEDCAD 4 for Windows Copyright 1998 Pamela J. Schwab Civil Software Design 13 o Retardance Slope (/o) Freeboard Freeboard Freeboard Limiting Velocity Clams Depth (ft) % of Depth Mult. x (VxD) (fps) 0.1 D, B I 7.0 Vegetated Channel Results: Stability Stability Class D w/o Class D w/ Freeboard Freeboard Capacity Capacity Class B w/o Class B w/ Freeboard Freeboard Design Discharge: 3.99 cfs 3.99 cfs Depth: 1.55 ft 2.57 ft Top Width: 6.20 ft 10.30 It Velocity: 0.62 fps 0.23 fps X-Section Area: 6.42 sq ft 17.68 sq ft Hydraulic Radius: 0.886 1.471 Froude Number: 0.11 0.03 Roughness Coefficient: 0.0700 0.2702 Filename: Cad1352-31.sc4 Printed 01-26-2000 SEDCAD 4 for Windows Copyright 1998 Pamela J. Schwab CiNI Software Design 14 Subwatershed Hydrology Detail; Stru # SWS # SWS Area (ac) Time of Conc (hrs) Musk K (hrs) Musk X Curve Number UHS Peak Discharge (C's) Runoff Volume (ac-R) #1 1 0.196 0.120 0.120 0.214 98.000 TR55 0.68 0.135 2 0.110 0.077 0.077 0.196 98.000 TR55 I 0.38 0.076 3 2.990 0.052 0.052 0.173 92.000 TR55 10.17 1.878 3.295 11.22 2.089 #2 3.295 11.21 2.089 #3 1 0.196 0.120 0.120 0.214 98.000 TR55 0.68 0.135 2 0.110 0.078 0.078 0.196 98.000 TRSS 0.38 0.076 3 0.399 0.030 0.030 0.173 92.000 TR55 1.36 0.250 4 0.940 0.030 0.030 0.173 92.000 TR55 3.20 0.590 5 0.239 0.084 0.084 0.196 98.000 TRS5 0.83 0.165 6 1.186 0.046 0.046 0.173 92.000 TR55 4.03 0.745 6.364 21.68 4.049 #4 6.364 21.67 4.049 #5 1 0.680 0.046 0.046 0.173 92.000 TR55 2.31 0.427 7.044 23.98 4.476 #6 � 7.044 23.97 4.476 #7 1 0.797 0.046 0.046 0.173 92.000 TR55 2.71 0.501 7.841 26.68 4.977 #8 7.841 26.67 4.977 #9 7.841 26.67 4.977 #10 7.841 3.99 4.977 Subwatershed Time of Concentration Details: Stru SWS Land Flow Condition Slope (%) Vert Dist. Horiz. Dist. Velocity Time (hrs) R) (fps) #1 1 7. Paved area and small upland 0.40 2.20 550.00 1.270 0.120 gullies #1 1 Time of Concentration: 0.120 #1 2 7• Paved area and small upland 0.30 0.92 306.66 1.100 0.077 gullies #1 2 Time of Concentration: 0.077 Filename: Cad1352-31.sc4 Printed 01-25-2000 SEDCAD 4 for Windows Copyright 1998 Pamela J. SChwab Civil Software Design 15 Stru # SWS # Land Flow Condition Slope (%) Vert. Dist (ft) Horiz. Dist. (ft) Velocity (fps) Time (hrs) #1 3 7. Paved area and small upland gullies 0.20 0.34 170.00 0.900 0.052 #1 3 Time of Concentration: 0.052 #3 1 7. Paved area and small upland gullies 0.40 2.20 550.00 1.270 0.120 #3 1 Time of Concentration: 0.120 #3 2 7. Paved area and small upland gullies 0.30 0.92 309.00 1.100 0.078 #3 2 Time of Concentration: 0.078 #3 3 7• Paved area and small upland gullies 0.20 0.19 99.00 0.900 0.030 #3 3 Time of Concentration: 0.030 #3 4 7. Paved area and small upland gullies 0.20 0.20 100.00 0.900 0.030 #3 4 Time of Concentration: 0.030 #3 5 7. Paved area and small upland gullies 0.30 1.00 336.00 1.100 0.084 #3 5 Time of Concentration: 0.084 #3 6 7. Paved area and small upland gullies 0.20 0.30 150.00 0.900 0.046 #3 6 Time of Concentration: 0.046 #5 1 7. Paved area and small upland gullies 0.20 0.30 150.00 0.900 0.046 #5 1 Time of Concentration: 0.046 #7 1 7. Paved area and small upland gullies 0.20 0.30 150.00 0.900 0.046 #7 1 Time of Concentration: 0.046 Subwatershed Muskingum Routing Details; Stru # Sw5 # Land Flow Condition Slope (%) Vert. Dist (ft) Horiz. Dist. (ft) Velocity (fps) Time (hrs) #1 1 7. Paved area and small upland gullies 0.40 2.20 550.00 1.270 0.120 #1 1 Muskingum K: 0.120 #1 2 7• Paved area and small upland gullies 0.30 0.92 306.66 1.100 0.077 #1 2 Muskingum K: 0.077 #1 3 7. Paved area and small upland gullies 0.20 0.34 170.00 0.900 0.052 #1 3 Muskingum K: 0.052 #3 1 7. Paved area and small upland gullies 0.40 2.20 550.00 1.270 0.120 #3 1 Muskingum K: 0.120 #3 2 7. Paved area and small upland gullies 0.30 0.92 309.00 1.100 0.078 #3 2 Muskingum K: 0.078 Filename: Cad1352-31.scA Printed 01-25-2000 SEDCAD 4 for Windows Copyright 1998 Pamela J. Schwab Civil Software Design M' SW SWS Land Flow Condition Slope ("/o) Vert. Dist. Horiz. Dist. Velocity Time (hrs) #3 3 7. Paved area and small upland 0.20 0.19 99.00 0.900 0.030 gullies #3 3 Muskingum K: 0.030 #3 4 7• Paved area and small upland 0.20 0.20 100.00 0.900 0.030 gullies #3 4 Muskingum K: 0.030 #3 5 7• Paved area and small upland 0.30 1.00 336.00 1.100 0.084 gullies #3 5 Muskingum K: 0.084 #3 6 7• Paved area and small upland 0.20 0.30 150.00 0.900 0.046 gullies #3 6 Muskingum K: 0.046 #5 1 7• Paved area and small upland 0.20 0.30 150.00 0.900 0.046 gullies #5 1 Muskingum K: 0.046 #7 1 7. Paved area and small upland 0.20 0.30 150.00 0.900 0.046 gullies #7 1 Muskingum K: 0.046 Filename: Cad1352-31.sc4 Printed 01-25-2000 State of North Carolina Department of Environment and Natural Resources Wilmington Regional Office James B. Hunt, Jr., Governor Bill Holman, Secretary Division of Water Quality January 18, 2000 Mr. David A. Horton, Owner 128 Little Nine Dr. Morehead City, NC 28557 Dear Mr. Horton: 0 WA C R NORTH CAROUNA DEPARTMENT OF ENVIRONMENT AND NI URA RESOURCES Subject: ACKNOWLEDGMENT OF RECEIPT AND REQUEST FOR ADDITIONAL INFORMATION Stormwater Project No. S W 8 991202 David A. Horton Carteret County The Wilmington Regional Office received a Stormwater Management Permit Application for David A. Horton on December 1, 1999. A preliminary review of that information has determined that the application is not complete. The following information is needed to continue the stormwater review: Section III. numbers 2 and 6 need to be filled in completely. For #6 on page 2 of 4 please fill in the receiving stream name and if you can not find the classification for the stream let me know and I will find it on your behalf. I am retuming the 4 page application and the 4 page supplement form for needed modifications. 2. Please fill in Section IV. # 2 on page 3 of 4 of the application. These deed restrictions and protective covenants must be complete and recorded prior to the sale/construction of any lot. From what is given on the application and plans, there seems to be approximately 16,350 square feet of impervious surface per each of the 15 buildable lots. Please verify and fill in the deed restriction blank. If Mr. C.T. Clayton and/or Brad Suitt & Assoc., P.A. will be resubmitting any information on your behalf, please fill in their names under Section VII. on page 4 of 4. 4. On page 3 of 4 of the Wet Detention Basin Supplement form, please correct the sediment removal benchmarks from "elevations" to "depths" below the permanent pool elevation of22.0. Please clearly define the property/project lines for the subdivision on the plans. ,1t 6. Please delineate the drainage area for the pond, all impervious areas are to be included. If the layout of each lot has not been decided yet, than please note on the plans that the lots will be graded such that all impervious runoff will be directed toward the street/pond. Note that all roof drains are included and must be directed so as to be picked up by the pond. 7. Please dimension the permanent pool of the pond on the plans. 127 Cardinal Dr. Ext., Wilmington, North Carolina 28405 Telephone 910-395-3900 FAX 910-350-2004 An Equal Opportunity Affirmative Action Employer 50% recycled/]0°/ post -consumer paper Mr. Horton January 18, 2000 Stormwater Project No. SW8 991202 8. Please provide the vegetated filter required for ponds designed for 85% TSS removal. These filters are not to be simply connector ditches and they cannot. have any other water flowing through them other than what is coming from the pond. Please also provide a detail of the . vegetated filter as well as the calculations needed to show the design width of the filter will have non erosive flow. The filter will also need to have the permanent grassed vegetation to be used specified. Note that these filters are to be designed so that the only time there is standing water in them should be when the pond is draining. I am including a sample detail of a vegetated filter for your reference. The filter should be at least 30 feet in length and have a flow spreader mechanism. 9. The 6:1 vegetative shelf should be around the main pond only. I have enclosed a pond section to help show this.. 10. Please raise the southern end of the forebay weir up to at least 1 foot below the permanent pool elevation, i.e. 21.00 feet MSL. X 11. The required 3:1, length : width ratio for the pond has not been meet, please correct. �t 12. Currently the forebay is only holding approximately 12% of the permanent pool volume. Please increase the volume of the forebay to hold approximately 20% of the total permanent pool volume. 13. Please reference the project number above on all correspondence. Please note that this request for additional information is in response to a preliminary review. The requested information should be received by this Office prior to February 18, 2000, or the application will be returned as incomplete. Theyetuin of a project will necessitate resubmittal of all required items, including the application fee. The Division is allowed 90 days from the receipt of a completed application to issue the permit. The construction of any impervious surfaces, other than a construction entrance under an approved Sedimentation Erosion Control Plan, is a violation of NCGS 143-215.1 and is subject to enforcement action pursuant to NCGS 143-215.6A. If you have any questions concerning this matter please feel free to call me at (910) 395-3900. Sincerely, Scott Vinson Environmental Engineer RSS/sav: S:\WQS\STORMWAT\ADDINFO\991202.JAN cc: Wilmington Regional Office C.T. Clayton, P.E. 5TORMWATER MAINTENANCE PLAN for DAVID A. HORTON COMMERCIAL PARK Morehead Townehip Carteret County North Carolina October 2,1999 1- TABLE of CONTENT5 Narrative............................................................................................................................................................................... 3 MaintenancePlan............................................................................................................................................................... 5 -2- NARRATIVE The purpose of the project is to construct a stormwater retention pond to serve 9.41 acre Commercial Park. The project is in Morehead Township, Carteret County, North Carolina and is being developed by David A. Horton. The work proposed will include excavation of the stormwater retention pond for the Commercial Park, and construction of its on site storm drainage system. atC-Df-sad 2t= 5ee Plan. Land use in the vicinity is commercial and residential. The property to the southeast is owned by David A. Horton, all other properties adjoining are owned by others, and will not be affected by the work. A temporary gravel construction entrance/exit will be installed at the east project entrance. During wet weather it may be necessary to wash vehicle tires at this location. The entrance will be graded so that runoff water will be directed away from proposed roadway. As soon as final grade is reached on the proposed roadway, the subgrade will be stabilized with a 6-inch course of NC DOT standard size ABC stone to prevent erosion and dust during the construction prior to paving. Slopes will be lightly roughened by disking just prior to vegetating. 5urface stabilization will be accomplished with vegetation and mulch as specified in the vegetation plan. Roadway base courses will fie installed as soon as finished grade is reached. Dust control is not expected to be a problem due to the small area of exposure. 51hould excessive dust be generated, it will be controlled by sprinkling with water. vein The project site soils consists mainly of sand, silt and clay. The stormwater collection system described herein and on the attached plan will provide the following methods for control of sediments and for removal of pollutants from the developed site runoff. 1. Collection of all runoff from the site during development of the stormwater retention pond with controlled discharge. -3- 2. Retention of the first one (1) inch of rainfall of runoff on the roadway and proposed parking and building areas into the stormwater retention pond. This runoff will drain over a 2 to 5 day period into the grass -lined Swale before draining into an existing Swale. 3. The retention time for the pond are set at 2.58 days with a total outfall of 8592 cf/day from a 2 inch diameter orifice. 4. The stormwater runoff in excess of the first one (1) inch of rainfall will discharge from the stormwater retention pond into a decant orifice structure. The storm pool elevation is set at 23.85' ABV M51- with an additional 11' emergency discharge, at elevation 24.0' adjacent to the existing ditch, as shown on the plan. 5. The entire project site to be served by the stormwater retention pond as shown on the "5tormwater Management flan of David A. Horton". 6. No 404 wetlands have been determined to be on this site. 7. Seeding specifications shall be as specified in the approved Erosion and Sedimentation Control Plan. -4- MAINTENANCE PLAN The Owner Shall maintain the pond during the construction phase of the project and after construction is completed for all routine and non -routine maintenance tasks. The Owner shall also be responsible for the perpetual care of the stormwater retention pond. All erosion and sediment control practices shall be checked for stability and proper operation following every runoff producing rainfall and in no case less than once every week during construction. All repairs shall be made immediately and shall be in accordance with the approved Erosion and Sedimentation Control Plan. The stormwater retention pond shall be inspected during the construction phase of the project following every runoff producing rainfall and in no case less than once a week. Check the embankment, spillway, outlet, and Swale for erosion damage, and inspect the embankment also for piping and settlement. Make all necessary repairs immediately. Remove all trash and other debris from around the decant orifice structure and from around the pool area. Periodic inspection of the discharge orifice shall assure that the system is not clogged. The retention pond shall be inspected for a build-up of sediment. If and when the sediment layer exceeds 18 inches thick on the average above the design grade, then this sediment shall be removed. At the close of the construction phase of the project, the pond shall be cleaned of excess sediment to the designed grade and begin functioning as stormwater retention pond. All regrading or repairing of the side slopes, seeding, mowing and any and all repairs shall be performed prior to close-out of the construction phase. The grass -lined Swale from pond overflow structure shall be properly inspected and maintained against erosion, weeds, and woody vegetation. All seeded areas shall be maintained to sustain the required vegetation. Any and all bare areas shall be replanted as necessary, with all repairs made immediately. Owner shall be responsible for all routine and non -routine requirements associated with the maintenance of the stormwater retention pond. Upon completion of earth disturbing activities and for 12 months following completion of the work, the owner shall inspect the site following every runoff producing rainfall. A written log shall be maintained of any needed repairs noted at the inspection, the name of the Contractor completing the repairs, and the date such repairs are completed. ISMWaLTA 1. Mowing. The side -slopes, embankment, buffer area, areas within the fence, areas adjacent to the emergency spillways and the grass -lined swales shall be mowed at least once a month during the main growing season and at least two other times during the year to prevent woody growth and to control weeds. Grass shall be mowed to a "meadow -like" condition and shall be maintained, according to Section 6.11 Permanent Seeding of the approved Erosion and Sedimentation Control Plan. 51 2. Insoe_ ctione The stormwater retention pond shall be inspected (at a minimum of) on an annual basis to ensure that the structure operates in the manner originally intended. Additional inspections shall be conducted during wet weather, or times of extreme weather to determine if each pond is functioning properly. Inspection priorities shall include (but not limited to) the following: checking the embankment for any erosion, subsidence, cracking, bare areas in the grass, and tree growth; the condition of the emergency spillway and adjacent ditch; the fence and adjacent planting buffers; the accumulation of sediment, clogging of the decant orifice structure; the adequacy of upstream and downstream channel erosion protection measures including any modifications which have occurred to the contributing watershed, and the pond structure including the stability of the side slopes. Inspections shall be carried out with "As -Built" retention pond plans 3. P-el �Littcr Removal. Debris and litter removal from the surface of the pond shall be included as a part of the periodic mowing operation. Particular attention shall be paid to any floating debris around the decant orifice structure, and the structure shall be checked for possible clogging. Any trash found within the area of the pond, ditch, and fence shall be removed and disposed of properly according the County regulations. 4. Erosion Control Corrective measures and repairs shall be done to the pond side slopes, embankment, emergency spillway and grass lined Swale where settlement, slumping, and erosion has occurred. Repair as necessary. Repair or replace the riprap protecting the channel near the outlet as required to stop the erosion. All repairs shall be done in accordance with the original plans and specifications. 5. Nuisance CDntrOl. Owner shall maintain the retention pond and adjacent areas so as to control the possible problems of weeds, More, algae, and insects. Proper maintenance shall take care of most problems except in times of extreme dry weather. Owner shall also use biological control against mosquito's and algae through the use of fish and fat head minnows when possible in lieu of chemical applications. 1. 5tructure. Repairs and Replacement Owner shall replace all deteriorated inlet/outlet works and decant orifice structure when deterioration from use and age causes them to fail and function properly. Owner shall be responsible for all costs incurred with their replacement. Replacement shall be in accordance with original plans and specifications. 2. 5ediment Removal. Owner shall be responsible for the removal of excess accumulated sediment in the pond when the storage capacity is significantly reduced from the design capacity due to the properly designed and functioning stormwater retention pond. Owner shall be responsible for all incurred costs of removal and proper disposal of the sediment in accordance with all local, state, and federal regulations. Sediment removal/clean out cycle for ctormwater retention pond is recommended on a ten to twenty year cycle. Owner shall every five (5) years measure the depth of sediment above design grade to determine rate of accumulation and to establish a time line for sediment removal. Irl 761 Cloytasr, P.E. Clayton, Professional Engineer Vv w LETTER OF TRANSMITTAL TO. Carol Miller NCDENR Wilmington Regional Office 127 Cardinal Drive Ext. Wilmington, NC 28405-3845 DATE: November 24, 1999 PROJECT NO: Cad 1352 TASK NO: 0001 RE: David A. Horton TRANSMITTAL NO: 1 PAGE 1 OF 1 WE ARE SENDING: ❑ Originals x Prints x Specifications x Calculations ❑ Shop Drawings ❑ Samples ❑ Other - Quantity Drawing No. Rev. Description Status 1 $420.00 check, Stormwater Management fee 1 Completed Application, Stormwater Management 2 Copies of Stormwater Maintenance Plan 2 Cad1352 Copies of Stormwater Management Plan Issue Status Code: A. Preliminary B. Fabrication Only C. For Information D. Bid E. Construction F. For Review & Comments G. For�lApppero=al_-__[_L..-H- See Remarks REMARKS: 'lol�` III c._� ci 19yy I°�t 2807 NEUSE BLVD. BLDG. N5 NEW cc: Brad L. Suitt David A. Horton Signed CAMy Documents\transCad1352sw.doc NC 28562 252 672-0304 FAX 7� C.T. ClaA W.� �: �.� �� .. a r, _::� 4�f ;�+y, �` " ;. � - - ;t : . �: �. .S i r r